Make down-conversion explicit from CFX_ByteString to CFX_ByteStringC.

Having this happen implicitly can be dangerous because the lifetime
has to be considered; we should have caught the "red bots" in
https://codereview.chromium.org/1847333004/#ps60001 at compile time.

Review URL: https://codereview.chromium.org/1853233002

6 files changed, 35 insertions, 20 deletions

diff --git a/fpdfsdk/pdfwindow/PWL_Edit.cpp b/fpdfsdk/pdfwindow/PWL_Edit.cpp
index f53f263470..64588f2dff 100644
--- a/fpdfsdk/pdfwindow/PWL_Edit.cpp
+++ b/fpdfsdk/pdfwindow/PWL_Edit.cpp
@@ -265,6 +265,7 @@ void CPWL_Edit::GetThisAppearanceStream(CFX_ByteTextBuf& sAppStream) {
       case PBS_SOLID: {
         sLine << "q\n" << GetBorderWidth() << " w\n"
               << CPWL_Utils::GetColorAppStream(GetBorderColor(), FALSE)
+                     .AsByteStringC()
               << " 2 J 0 j\n";
 
         for (int32_t i = 1; i < nCharArray; i++) {
@@ -281,6 +282,7 @@ void CPWL_Edit::GetThisAppearanceStream(CFX_ByteTextBuf& sAppStream) {
       case PBS_DASH: {
         sLine << "q\n" << GetBorderWidth() << " w\n"
               << CPWL_Utils::GetColorAppStream(GetBorderColor(), FALSE)
+                     .AsByteStringC()
               << " 2 J 0 j\n"
               << "[" << GetBorderDash().nDash << " " << GetBorderDash().nGap
               << "] " << GetBorderDash().nPhase << " d\n";
@@ -319,7 +321,8 @@ void CPWL_Edit::GetThisAppearanceStream(CFX_ByteTextBuf& sAppStream) {
 
   if (sEditSel.GetLength() > 0)
     sText << CPWL_Utils::GetColorAppStream(PWL_DEFAULT_SELBACKCOLOR)
-          << sEditSel;
+                 .AsByteStringC()
+          << sEditSel.AsByteStringC();
 
   wrTemp = CPWL_Utils::OverlapWordRange(wrVisible, wrSelBefore);
   CFX_ByteString sEditBefore = CPWL_Utils::GetEditAppStream(
@@ -327,8 +330,9 @@ void CPWL_Edit::GetThisAppearanceStream(CFX_ByteTextBuf& sAppStream) {
       m_pEdit->GetPasswordChar());
 
   if (sEditBefore.GetLength() > 0)
-    sText << "BT\n" << CPWL_Utils::GetColorAppStream(GetTextColor())
-          << sEditBefore << "ET\n";
+    sText << "BT\n"
+          << CPWL_Utils::GetColorAppStream(GetTextColor()).AsByteStringC()
+          << sEditBefore.AsByteStringC() << "ET\n";
 
   wrTemp = CPWL_Utils::OverlapWordRange(wrVisible, wrSelect);
   CFX_ByteString sEditMid = CPWL_Utils::GetEditAppStream(
@@ -338,7 +342,8 @@ void CPWL_Edit::GetThisAppearanceStream(CFX_ByteTextBuf& sAppStream) {
   if (sEditMid.GetLength() > 0)
     sText << "BT\n"
           << CPWL_Utils::GetColorAppStream(CPWL_Color(COLORTYPE_GRAY, 1))
-          << sEditMid << "ET\n";
+                 .AsByteStringC()
+          << sEditMid.AsByteStringC() << "ET\n";
 
   wrTemp = CPWL_Utils::OverlapWordRange(wrVisible, wrSelAfter);
   CFX_ByteString sEditAfter = CPWL_Utils::GetEditAppStream(
@@ -346,8 +351,9 @@ void CPWL_Edit::GetThisAppearanceStream(CFX_ByteTextBuf& sAppStream) {
       m_pEdit->GetPasswordChar());
 
   if (sEditAfter.GetLength() > 0)
-    sText << "BT\n" << CPWL_Utils::GetColorAppStream(GetTextColor())
-          << sEditAfter << "ET\n";
+    sText << "BT\n"
+          << CPWL_Utils::GetColorAppStream(GetTextColor()).AsByteStringC()
+          << sEditAfter.AsByteStringC() << "ET\n";
 
   if (HasFlag(PES_SPELLCHECK)) {
     CFX_ByteString sSpellCheck = CPWL_Utils::GetSpellCheckAppStream(
@@ -355,7 +361,8 @@ void CPWL_Edit::GetThisAppearanceStream(CFX_ByteTextBuf& sAppStream) {
     if (sSpellCheck.GetLength() > 0)
       sText << CPWL_Utils::GetColorAppStream(CPWL_Color(COLORTYPE_RGB, 1, 0, 0),
                                              FALSE)
-            << sSpellCheck;
+                   .AsByteStringC()
+            << sSpellCheck.AsByteStringC();
   }
 
   if (sText.GetLength() > 0) {
@@ -742,8 +749,9 @@ CFX_ByteString CPWL_Edit::GetTextAppearanceStream(
   CFX_ByteString sEdit = CPWL_Utils::GetEditAppStream(m_pEdit, ptOffset);
 
   if (sEdit.GetLength() > 0) {
-    sRet << "BT\n" << CPWL_Utils::GetColorAppStream(GetTextColor()) << sEdit
-         << "ET\n";
+    sRet << "BT\n"
+         << CPWL_Utils::GetColorAppStream(GetTextColor()).AsByteStringC()
+         << sEdit.AsByteStringC() << "ET\n";
   }
 
   return sRet.GetByteString();
diff --git a/fpdfsdk/pdfwindow/PWL_Icon.cpp b/fpdfsdk/pdfwindow/PWL_Icon.cpp
index 560f8e0e32..69f9e599da 100644
--- a/fpdfsdk/pdfwindow/PWL_Icon.cpp
+++ b/fpdfsdk/pdfwindow/PWL_Icon.cpp
@@ -42,7 +42,7 @@ CFX_ByteString CPWL_Image::GetImageAppStream() {
     sAppStream << mt.GetA() << " " << mt.GetB() << " " << mt.GetC() << " "
                << mt.GetD() << " " << mt.GetE() << " " << mt.GetF() << " cm\n";
 
-    sAppStream << "0 g 0 G 1 w /" << sAlias << " Do\n"
+    sAppStream << "0 g 0 G 1 w /" << sAlias.AsByteStringC() << " Do\n"
                << "Q\n";
   }
 
diff --git a/fpdfsdk/pdfwindow/PWL_Label.cpp b/fpdfsdk/pdfwindow/PWL_Label.cpp
index cfbeb4362c..8c5b0676d7 100644
--- a/fpdfsdk/pdfwindow/PWL_Label.cpp
+++ b/fpdfsdk/pdfwindow/PWL_Label.cpp
@@ -118,7 +118,8 @@ CFX_FloatRect CPWL_Label::GetContentRect() const {
 void CPWL_Label::GetThisAppearanceStream(CFX_ByteTextBuf& sAppStream) {
   CPWL_Wnd::GetThisAppearanceStream(sAppStream);
 
-  sAppStream << GetTextAppearanceStream(CFX_FloatPoint(0.0f, 0.0f));
+  sAppStream << GetTextAppearanceStream(CFX_FloatPoint(0.0f, 0.0f))
+                    .AsByteStringC();
 }
 
 CFX_ByteString CPWL_Label::GetTextAppearanceStream(
@@ -127,8 +128,9 @@ CFX_ByteString CPWL_Label::GetTextAppearanceStream(
   CFX_ByteString sEdit = CPWL_Utils::GetEditAppStream(m_pEdit, ptOffset);
 
   if (sEdit.GetLength() > 0) {
-    sRet << "BT\n" << CPWL_Utils::GetColorAppStream(GetTextColor()) << sEdit
-         << "ET\n";
+    sRet << "BT\n"
+         << CPWL_Utils::GetColorAppStream(GetTextColor()).AsByteStringC()
+         << sEdit.AsByteStringC() << "ET\n";
   }
 
   return sRet.GetByteString();
diff --git a/fpdfsdk/pdfwindow/PWL_ListBox.cpp b/fpdfsdk/pdfwindow/PWL_ListBox.cpp
index d39d8419a6..ccccc77dcd 100644
--- a/fpdfsdk/pdfwindow/PWL_ListBox.cpp
+++ b/fpdfsdk/pdfwindow/PWL_ListBox.cpp
@@ -118,21 +118,25 @@ void CPWL_ListBox::GetThisAppearanceStream(CFX_ByteTextBuf& sAppStream) {
 
       CFX_FloatPoint ptOffset(rcItem.left, (rcItem.top + rcItem.bottom) * 0.5f);
       if (m_pList->IsItemSelected(i)) {
-        sListItems << CPWL_Utils::GetRectFillAppStream(
-            rcItem, PWL_DEFAULT_SELBACKCOLOR);
+        sListItems << CPWL_Utils::GetRectFillAppStream(rcItem,
+                                                       PWL_DEFAULT_SELBACKCOLOR)
+                          .AsByteStringC();
         CFX_ByteString sItem =
             CPWL_Utils::GetEditAppStream(m_pList->GetItemEdit(i), ptOffset);
         if (sItem.GetLength() > 0) {
           sListItems << "BT\n"
                      << CPWL_Utils::GetColorAppStream(PWL_DEFAULT_SELTEXTCOLOR)
-                     << sItem << "ET\n";
+                            .AsByteStringC()
+                     << sItem.AsByteStringC() << "ET\n";
         }
       } else {
         CFX_ByteString sItem =
             CPWL_Utils::GetEditAppStream(m_pList->GetItemEdit(i), ptOffset);
         if (sItem.GetLength() > 0) {
-          sListItems << "BT\n" << CPWL_Utils::GetColorAppStream(GetTextColor())
-                     << sItem << "ET\n";
+          sListItems << "BT\n"
+                     << CPWL_Utils::GetColorAppStream(GetTextColor())
+                            .AsByteStringC()
+                     << sItem.AsByteStringC() << "ET\n";
         }
       }
     }
diff --git a/fpdfsdk/pdfwindow/PWL_ScrollBar.cpp b/fpdfsdk/pdfwindow/PWL_ScrollBar.cpp
index 9db2aea35b..a96cf5f2a5 100644
--- a/fpdfsdk/pdfwindow/PWL_ScrollBar.cpp
+++ b/fpdfsdk/pdfwindow/PWL_ScrollBar.cpp
@@ -670,7 +670,8 @@ void CPWL_ScrollBar::GetThisAppearanceStream(CFX_ByteTextBuf& sAppStream) {
 
     sButton << "q\n";
     sButton << "0 w\n"
-            << CPWL_Utils::GetColorAppStream(GetBackgroundColor(), TRUE);
+            << CPWL_Utils::GetColorAppStream(GetBackgroundColor(), TRUE)
+                   .AsByteStringC();
     sButton << rectWnd.left << " " << rectWnd.bottom << " "
             << rectWnd.right - rectWnd.left << " "
             << rectWnd.top - rectWnd.bottom << " re b Q\n";
diff --git a/fpdfsdk/pdfwindow/PWL_Signature.cpp b/fpdfsdk/pdfwindow/PWL_Signature.cpp
index 72b6ebe7c3..221922972f 100644
--- a/fpdfsdk/pdfwindow/PWL_Signature.cpp
+++ b/fpdfsdk/pdfwindow/PWL_Signature.cpp
@@ -42,7 +42,7 @@ void CPWL_Signature_Image::DrawThisAppearance(CFX_RenderDevice* pDevice,
 
 void CPWL_Signature_Image::GetThisAppearanceStream(
     CFX_ByteTextBuf& sAppStream) {
-  sAppStream << CPWL_Image::GetImageAppStream();
+  sAppStream << CPWL_Image::GetImageAppStream().AsByteStringC();
 }
 
 void CPWL_Signature_Image::GetScale(FX_FLOAT& fHScale, FX_FLOAT& fVScale) {