flush but do not release skia driver

Most calls to the Skia Driver combine flushing
the draw cache with deleting the driver itself.

Progressive drawing needs to flush the cache to
keep drawing in order, but the driver must remain
for the next progressive draw.

R=dsinclair@chromium.org, hnakashima@chromium.org
Bug: pdfium:833
Change-Id: I311f80b2dc0ef6e4df9a3a0f082ae076cb7a591f
Reviewed-on: https://pdfium-review.googlesource.com/8890
Reviewed-by: dsinclair <dsinclair@chromium.org>
Commit-Queue: dsinclair <dsinclair@chromium.org>

7 files changed, 24 insertions, 12 deletions

diff --git a/core/fpdfapi/render/cpdf_renderstatus.cpp b/core/fpdfapi/render/cpdf_renderstatus.cpp
index e033f26093..a08650500b 100644
--- a/core/fpdfapi/render/cpdf_renderstatus.cpp
+++ b/core/fpdfapi/render/cpdf_renderstatus.cpp
@@ -944,7 +944,7 @@ CFX_RetainPtr<CFX_DIBitmap> DrawPatternBitmap(CPDF_Document* pDoc,
   context.AppendLayer(pPattern->form(), &mtPattern2Bitmap);
   context.Render(&bitmap_device, &options, nullptr);
 #if defined _SKIA_SUPPORT_PATHS_
-  bitmap_device.Flush();
+  bitmap_device.Flush(true);
   pBitmap->UnPreMultiply();
 #endif
   return pBitmap;
@@ -1602,7 +1602,7 @@ bool CPDF_RenderStatus::ProcessTransparency(CPDF_PageObject* pPageObj,
                            m_bDropObjects, pFormResource, true);
   bitmap_render.ProcessObjectNoClip(pPageObj, &new_matrix);
 #if defined _SKIA_SUPPORT_PATHS_
-  bitmap_device.Flush();
+  bitmap_device.Flush(true);
   bitmap->UnPreMultiply();
 #endif
   m_bStopped = bitmap_render.m_bStopped;
diff --git a/core/fxge/cfx_renderdevice.cpp b/core/fxge/cfx_renderdevice.cpp
index 407c090c73..279e720d1e 100644
--- a/core/fxge/cfx_renderdevice.cpp
+++ b/core/fxge/cfx_renderdevice.cpp
@@ -375,13 +375,16 @@ CFX_RenderDevice::CFX_RenderDevice()
 CFX_RenderDevice::~CFX_RenderDevice() {
   RestoreState(false);
 #if defined _SKIA_SUPPORT_ || defined _SKIA_SUPPORT_PATHS_
-  Flush();
+  Flush(true);
 #endif
 }
 
 #if defined _SKIA_SUPPORT_ || defined _SKIA_SUPPORT_PATHS_
-void CFX_RenderDevice::Flush() {
-  m_pDeviceDriver.reset();
+void CFX_RenderDevice::Flush(bool release) {
+  if (release)
+    m_pDeviceDriver.reset();
+  else
+    m_pDeviceDriver->Flush();
 }
 #endif
 
diff --git a/core/fxge/cfx_renderdevice.h b/core/fxge/cfx_renderdevice.h
index ef15718d58..ad8e487749 100644
--- a/core/fxge/cfx_renderdevice.h
+++ b/core/fxge/cfx_renderdevice.h
@@ -274,7 +274,7 @@ class CFX_RenderDevice {
                                int blend_type);
 #endif
 #if defined _SKIA_SUPPORT_ || defined _SKIA_SUPPORT_PATHS_
-  void Flush();
+  void Flush(bool release);
 #endif
 
  private:
diff --git a/core/fxge/skia/fx_skia_device.cpp b/core/fxge/skia/fx_skia_device.cpp
index 855699a4be..523c8a28e8 100644
--- a/core/fxge/skia/fx_skia_device.cpp
+++ b/core/fxge/skia/fx_skia_device.cpp
@@ -2595,7 +2595,7 @@ bool CFX_DefaultRenderDevice::Create(
 }
 
 CFX_DefaultRenderDevice::~CFX_DefaultRenderDevice() {
-  Flush();
+  Flush(true);
 }
 
 #ifdef _SKIA_SUPPORT_
diff --git a/fpdfsdk/fpdf_progressive.cpp b/fpdfsdk/fpdf_progressive.cpp
index 1b10a119dc..2411869904 100644
--- a/fpdfsdk/fpdf_progressive.cpp
+++ b/fpdfsdk/fpdf_progressive.cpp
@@ -61,7 +61,7 @@ DLLEXPORT int STDCALL FPDF_RenderPageBitmap_Start(FPDF_BITMAP bitmap,
                          rotate, flags, false, &IPauseAdapter);
 
 #ifdef _SKIA_SUPPORT_PATHS_
-  pDevice->Flush();
+  pDevice->Flush(false);
   pBitmap->UnPreMultiply();
 #endif
   if (pContext->m_pRenderer) {
@@ -86,7 +86,7 @@ DLLEXPORT int STDCALL FPDF_RenderPage_Continue(FPDF_PAGE page,
     pContext->m_pRenderer->Continue(&IPauseAdapter);
 #ifdef _SKIA_SUPPORT_PATHS_
     CFX_RenderDevice* pDevice = pContext->m_pDevice.get();
-    pDevice->Flush();
+    pDevice->Flush(false);
     pDevice->GetBitmap()->UnPreMultiply();
 #endif
     return CPDF_ProgressiveRenderer::ToFPDFStatus(
@@ -97,6 +97,15 @@ DLLEXPORT int STDCALL FPDF_RenderPage_Continue(FPDF_PAGE page,
 
 DLLEXPORT void STDCALL FPDF_RenderPage_Close(FPDF_PAGE page) {
   CPDF_Page* pPage = CPDFPageFromFPDFPage(page);
-  if (pPage)
+  if (pPage) {
+#ifdef _SKIA_SUPPORT_PATHS_
+    CPDF_PageRenderContext* pContext = pPage->GetRenderContext();
+    if (pContext && pContext->m_pRenderer) {
+      CFX_RenderDevice* pDevice = pContext->m_pDevice.get();
+      pDevice->Flush(true);
+      pDevice->GetBitmap()->UnPreMultiply();
+    }
+#endif
     pPage->SetRenderContext(nullptr);
+  }
 }
diff --git a/fpdfsdk/fpdfformfill.cpp b/fpdfsdk/fpdfformfill.cpp
index 627bd0a925..e541b81cc3 100644
--- a/fpdfsdk/fpdfformfill.cpp
+++ b/fpdfsdk/fpdfformfill.cpp
@@ -144,7 +144,7 @@ void FFLCommon(FPDF_FORMHANDLE hHandle,
 #endif  // PDF_ENABLE_XFA
   }
 #ifdef _SKIA_SUPPORT_PATHS_
-  pDevice->Flush();
+  pDevice->Flush(true);
   holder->UnPreMultiply();
 #endif
 }
diff --git a/fpdfsdk/fpdfview.cpp b/fpdfsdk/fpdfview.cpp
index f8823c994c..956e6db671 100644
--- a/fpdfsdk/fpdfview.cpp
+++ b/fpdfsdk/fpdfview.cpp
@@ -940,7 +940,7 @@ DLLEXPORT void STDCALL FPDF_RenderPageBitmap(FPDF_BITMAP bitmap,
                          rotate, flags, true, nullptr);
 
 #ifdef _SKIA_SUPPORT_PATHS_
-  pDevice->Flush();
+  pDevice->Flush(true);
   pBitmap->UnPreMultiply();
 #endif
   pPage->SetRenderContext(nullptr);