Support the device font cache

Reuse the Skia typeface on sucessive text draw calls.
This reduces the SKP size by 100x for some documents.

Note that this does not use a smart pointer for the
Skia typeface object. The downside of doing so is that
it requires all clients that include fx_font.h to also
have access to Skia.

In this specific case, it is preferable to have a
forward declared class to isolate Skia from the rest of PDFium.

R=dsinclair,tsepez@chromium.org

Review URL: https://codereview.chromium.org/1837113004

4 files changed, 51 insertions, 3 deletions

diff --git a/core/fxge/ge/DEPS b/core/fxge/ge/DEPS
new file mode 100644
index 0000000000..6492756b7e
--- /dev/null
+++ b/core/fxge/ge/DEPS
@@ -0,0 +1,3 @@
+include_rules = [
+  '+third_party/skia/include'
+]
diff --git a/core/fxge/ge/fx_ge_text.cpp b/core/fxge/ge/fx_ge_text.cpp
index 1d18ecd377..0815bfaa67 100644
--- a/core/fxge/ge/fx_ge_text.cpp
+++ b/core/fxge/ge/fx_ge_text.cpp
@@ -9,6 +9,11 @@
 #include "core/include/fxge/fx_freetype.h"
 #include "core/include/fxge/fx_ge.h"
 
+#ifdef _SKIA_SUPPORT_
+#include "third_party/skia/include/core/SkStream.h"
+#include "third_party/skia/include/core/SkTypeface.h"
+#endif
+
 #undef FX_GAMMA
 #undef FX_GAMMA_INVERSE
 #define FX_GAMMA(value) (value)
@@ -1198,6 +1203,20 @@ CFX_FaceCache* CFX_FontCache::GetCachedFace(CFX_Font* pFont) {
   return face_cache;
 }
 
+#ifdef _SKIA_SUPPORT_
+CFX_TypeFace* CFX_FontCache::GetDeviceCache(CFX_Font* pFont) {
+  return GetCachedFace(pFont)->GetDeviceCache(pFont);
+}
+
+CFX_TypeFace* CFX_FaceCache::GetDeviceCache(CFX_Font* pFont) {
+  if (!m_pTypeface) {
+    m_pTypeface = SkTypeface::CreateFromStream(
+        new SkMemoryStream(pFont->GetFontData(), pFont->GetSize()));
+  }
+  return m_pTypeface;
+}
+#endif
+
 void CFX_FontCache::ReleaseCachedFace(CFX_Font* pFont) {
   FXFT_Face internal_face = pFont->GetFace();
   const bool bExternal = !internal_face;
@@ -1237,7 +1256,14 @@ void CFX_FontCache::FreeCache(FX_BOOL bRelease) {
   }
 }
 
-CFX_FaceCache::CFX_FaceCache(FXFT_Face face) : m_Face(face) {}
+CFX_FaceCache::CFX_FaceCache(FXFT_Face face)
+    : m_Face(face)
+#ifdef _SKIA_SUPPORT_
+      ,
+      m_pTypeface(nullptr)
+#endif
+{
+}
 
 CFX_FaceCache::~CFX_FaceCache() {
   for (const auto& pair : m_SizeMap) {
@@ -1248,7 +1274,11 @@ CFX_FaceCache::~CFX_FaceCache() {
     delete pair.second;
   }
   m_PathMap.clear();
+#ifdef _SKIA_SUPPORT_
+  SkSafeUnref(m_pTypeface);
+#endif
 }
+
 #if _FXM_PLATFORM_ != _FXM_PLATFORM_APPLE_
 void CFX_FaceCache::InitPlatform() {}
 #endif
diff --git a/core/fxge/skia/fx_skia_device.cpp b/core/fxge/skia/fx_skia_device.cpp
index 745c9b50fd..e61dda68d4 100644
--- a/core/fxge/skia/fx_skia_device.cpp
+++ b/core/fxge/skia/fx_skia_device.cpp
@@ -320,8 +320,7 @@ FX_BOOL CFX_SkiaDeviceDriver::DrawDeviceText(int nChars,
                                              uint32_t color,
                                              int alpha_flag,
                                              void* pIccTransform) {
-  SkAutoTUnref<SkTypeface> typeface(SkTypeface::CreateFromStream(
-      new SkMemoryStream(pFont->GetFontData(), pFont->GetSize())));
+  CFX_TypeFace* typeface = pCache->GetDeviceCache(pFont);
   SkPaint paint;
   paint.setAntiAlias(true);
   paint.setColor(color);
diff --git a/core/include/fxge/fx_font.h b/core/include/fxge/fx_font.h
index c52e614e97..4e2b97e677 100644
--- a/core/include/fxge/fx_font.h
+++ b/core/include/fxge/fx_font.h
@@ -27,6 +27,12 @@ class CFX_SubstFont;
 class CTTFontDesc;
 class IFX_SystemFontInfo;
 
+#ifdef _SKIA_SUPPORT_
+class SkTypeface;
+
+using CFX_TypeFace = SkTypeface;
+#endif
+
 #define FXFONT_FIXED_PITCH 0x01
 #define FXFONT_SERIF 0x02
 #define FXFONT_SYMBOLIC 0x04
@@ -452,6 +458,9 @@ class CFX_FontCache {
   CFX_FaceCache* GetCachedFace(CFX_Font* pFont);
   void ReleaseCachedFace(CFX_Font* pFont);
   void FreeCache(FX_BOOL bRelease = FALSE);
+#ifdef _SKIA_SUPPORT_
+  CFX_TypeFace* GetDeviceCache(CFX_Font* pFont);
+#endif
 
  private:
   using CFX_FTCacheMap = std::map<FXFT_Face, CFX_CountedFaceCache*>;
@@ -490,6 +499,10 @@ class CFX_FaceCache {
                                     uint32_t glyph_index,
                                     int dest_width);
 
+#ifdef _SKIA_SUPPORT_
+  CFX_TypeFace* GetDeviceCache(CFX_Font* pFont);
+#endif
+
  private:
   CFX_GlyphBitmap* RenderGlyph(CFX_Font* pFont,
                                uint32_t glyph_index,
@@ -516,6 +529,9 @@ class CFX_FaceCache {
   std::map<CFX_ByteString, CFX_SizeGlyphCache*> m_SizeMap;
   std::map<uint32_t, CFX_PathData*> m_PathMap;
   CFX_DIBitmap* m_pBitmap;
+#ifdef _SKIA_SUPPORT_
+  CFX_TypeFace* m_pTypeface;
+#endif
 };
 
 struct FXTEXT_GLYPHPOS {