[WIP Experiment] Implement mix-blend-mode in GLRenderer using shaders.

cc/output/gl_renderer.h

Index: cc/output/gl_renderer.h
diff --git a/cc/output/gl_renderer.h b/cc/output/gl_renderer.h
index 75a5d6e720e76572268f2a7b5e32570c24647d83..bba583232c694bc8cae9f72d6e55ca1dd0fd1a19 100644
--- a/cc/output/gl_renderer.h
+++ b/cc/output/gl_renderer.h
@@ -143,12 +143,23 @@ class CC_EXPORT GLRenderer : public DirectRenderer {
                             const CheckerboardDrawQuad* quad);
   void DrawDebugBorderQuad(const DrawingFrame* frame,
                            const DebugBorderDrawQuad* quad);
+  static bool ShouldApplyBackgroundFilters(DrawingFrame* frame,
+                                           const RenderPassDrawQuad* quad);
+  static bool ShouldApplyBlendModeUsingShaders(const DrawQuad* quad);
+  static bool ShouldApplyBlendModeUsingBlendFunc(const DrawQuad* quad);
+  void ApplyBlendModeUsingBlendFunc(const DrawQuad* quad);
+  void RestoreBlendFuncToDefault(const DrawQuad* quad);
+  gfx::Rect GetBackdropBoundingBox(
+      DrawingFrame* frame,
+      const RenderPassDrawQuad* quad,
+      const gfx::Transform& contents_device_transform);
+  scoped_ptr<ScopedResource> GetBackdrop(const gfx::Rect& bounding_rect);
   scoped_ptr<ScopedResource> GetBackgroundWithFilters(
       DrawingFrame* frame,
       const RenderPassDrawQuad* quad,
-      const gfx::Transform& contents_device_transform,
       const gfx::Transform& contents_device_transformInverse,
-      bool* background_changed);
+      const ScopedResource* backdrop_texture,
+      const gfx::Rect& backdrop_bounding_rect);
   void DrawRenderPassQuad(DrawingFrame* frame, const RenderPassDrawQuad* quad);
   void DrawSolidColorQuad(const DrawingFrame* frame,
                           const SolidColorDrawQuad* quad);
@@ -254,26 +265,30 @@ class CC_EXPORT GLRenderer : public DirectRenderer {
       NonPremultipliedTextureBackgroundProgram;
 
   // Render surface shaders.
-  typedef ProgramBinding<VertexShaderPosTexTransform,
-                         FragmentShaderRGBATexAlpha> RenderPassProgram;
-  typedef ProgramBinding<VertexShaderPosTexTransform,
-                         FragmentShaderRGBATexAlphaMask> RenderPassMaskProgram;
-  typedef ProgramBinding<VertexShaderQuadTexTransformAA,
-                         FragmentShaderRGBATexAlphaAA> RenderPassProgramAA;
-  typedef ProgramBinding<VertexShaderQuadTexTransformAA,
-                         FragmentShaderRGBATexAlphaMaskAA>
+  typedef ProgramBindingWithBlendMode<VertexShaderPosTexTransform,
+                                      FragmentShaderRGBATexAlpha>
+      RenderPassProgram;
+  typedef ProgramBindingWithBlendMode<VertexShaderPosTexTransform,
+                                      FragmentShaderRGBATexAlphaMask>
+      RenderPassMaskProgram;
+  typedef ProgramBindingWithBlendMode<VertexShaderQuadTexTransformAA,
+                                      FragmentShaderRGBATexAlphaAA>
+      RenderPassProgramAA;
+  typedef ProgramBindingWithBlendMode<VertexShaderQuadTexTransformAA,
+                                      FragmentShaderRGBATexAlphaMaskAA>
       RenderPassMaskProgramAA;
-  typedef ProgramBinding<VertexShaderPosTexTransform,
-                         FragmentShaderRGBATexColorMatrixAlpha>
+  typedef ProgramBindingWithBlendMode<VertexShaderPosTexTransform,
+                                      FragmentShaderRGBATexColorMatrixAlpha>
       RenderPassColorMatrixProgram;
-  typedef ProgramBinding<VertexShaderQuadTexTransformAA,
-                         FragmentShaderRGBATexAlphaMaskColorMatrixAA>
+  typedef ProgramBindingWithBlendMode<
+      VertexShaderQuadTexTransformAA,
+      FragmentShaderRGBATexAlphaMaskColorMatrixAA>
       RenderPassMaskColorMatrixProgramAA;
-  typedef ProgramBinding<VertexShaderQuadTexTransformAA,
-                         FragmentShaderRGBATexAlphaColorMatrixAA>
+  typedef ProgramBindingWithBlendMode<VertexShaderQuadTexTransformAA,
+                                      FragmentShaderRGBATexAlphaColorMatrixAA>
       RenderPassColorMatrixProgramAA;
-  typedef ProgramBinding<VertexShaderPosTexTransform,
-                         FragmentShaderRGBATexAlphaMaskColorMatrix>
+  typedef ProgramBindingWithBlendMode<VertexShaderPosTexTransform,
+                                      FragmentShaderRGBATexAlphaMaskColorMatrix>
       RenderPassMaskColorMatrixProgram;
 
   // Video shaders.
@@ -307,22 +322,32 @@ class CC_EXPORT GLRenderer : public DirectRenderer {
 
   const TileCheckerboardProgram* GetTileCheckerboardProgram();
 
+  static int GetBlendModeIndex(SkXfermode::Mode blend_mode);
   const RenderPassProgram* GetRenderPassProgram(
-      TexCoordPrecision precision);
+      TexCoordPrecision precision,
+      SkXfermode::Mode = SkXfermode::kSrcOver_Mode);
   const RenderPassProgramAA* GetRenderPassProgramAA(
-      TexCoordPrecision precision);
+      TexCoordPrecision precision,
+      SkXfermode::Mode = SkXfermode::kSrcOver_Mode);
   const RenderPassMaskProgram* GetRenderPassMaskProgram(
-      TexCoordPrecision precision);
+      TexCoordPrecision precision,
+      SkXfermode::Mode = SkXfermode::kSrcOver_Mode);
   const RenderPassMaskProgramAA* GetRenderPassMaskProgramAA(
-      TexCoordPrecision precision);
+      TexCoordPrecision precision,
+      SkXfermode::Mode = SkXfermode::kSrcOver_Mode);
   const RenderPassColorMatrixProgram* GetRenderPassColorMatrixProgram(
-      TexCoordPrecision precision);
+      TexCoordPrecision precision,
+      SkXfermode::Mode = SkXfermode::kSrcOver_Mode);
   const RenderPassColorMatrixProgramAA* GetRenderPassColorMatrixProgramAA(
-      TexCoordPrecision precision);
+      TexCoordPrecision precision,
+      SkXfermode::Mode = SkXfermode::kSrcOver_Mode);
   const RenderPassMaskColorMatrixProgram* GetRenderPassMaskColorMatrixProgram(
-      TexCoordPrecision precision);
+      TexCoordPrecision precision,
+      SkXfermode::Mode = SkXfermode::kSrcOver_Mode);
   const RenderPassMaskColorMatrixProgramAA*
-      GetRenderPassMaskColorMatrixProgramAA(TexCoordPrecision precision);
+      GetRenderPassMaskColorMatrixProgramAA(
+          TexCoordPrecision precision,
+          SkXfermode::Mode = SkXfermode::kSrcOver_Mode);
 
   const TextureProgram* GetTextureProgram(
       TexCoordPrecision precision);
@@ -367,18 +392,22 @@ class CC_EXPORT GLRenderer : public DirectRenderer {
       nonpremultiplied_texture_background_program_[NumTexCoordPrecisions];
   TextureProgram texture_io_surface_program_[NumTexCoordPrecisions];
 
-  RenderPassProgram render_pass_program_[NumTexCoordPrecisions];
-  RenderPassProgramAA render_pass_program_aa_[NumTexCoordPrecisions];
-  RenderPassMaskProgram render_pass_mask_program_[NumTexCoordPrecisions];
-  RenderPassMaskProgramAA render_pass_mask_program_aa_[NumTexCoordPrecisions];
+  static const int kNumBlendModes = 16;
+  RenderPassProgram render_pass_program_[kNumBlendModes][NumTexCoordPrecisions];
+  RenderPassProgramAA
+      render_pass_program_aa_[kNumBlendModes][NumTexCoordPrecisions];
+  RenderPassMaskProgram
+      render_pass_mask_program_[kNumBlendModes][NumTexCoordPrecisions];
+  RenderPassMaskProgramAA
+      render_pass_mask_program_aa_[kNumBlendModes][NumTexCoordPrecisions];
   RenderPassColorMatrixProgram
-      render_pass_color_matrix_program_[NumTexCoordPrecisions];
-  RenderPassColorMatrixProgramAA
-      render_pass_color_matrix_program_aa_[NumTexCoordPrecisions];
-  RenderPassMaskColorMatrixProgram
-      render_pass_mask_color_matrix_program_[NumTexCoordPrecisions];
-  RenderPassMaskColorMatrixProgramAA
-      render_pass_mask_color_matrix_program_aa_[NumTexCoordPrecisions];
+      render_pass_color_matrix_program_[kNumBlendModes][NumTexCoordPrecisions];
+  RenderPassColorMatrixProgramAA render_pass_color_matrix_program_aa_
+      [kNumBlendModes][NumTexCoordPrecisions];
+  RenderPassMaskColorMatrixProgram render_pass_mask_color_matrix_program_
+      [kNumBlendModes][NumTexCoordPrecisions];
+  RenderPassMaskColorMatrixProgramAA render_pass_mask_color_matrix_program_aa_
+      [kNumBlendModes][NumTexCoordPrecisions];
 
   VideoYUVProgram video_yuv_program_[NumTexCoordPrecisions];
   VideoYUVAProgram video_yuva_program_[NumTexCoordPrecisions];