Fix HTML5 video blurry

cc/output/gl_renderer.cc

Index: cc/output/gl_renderer.cc
diff --git a/cc/output/gl_renderer.cc b/cc/output/gl_renderer.cc
index ac68a08c62f622ed275cca567de070aa52845e20..c15ee42492534af57a655049bfba30190b17e465 100644
--- a/cc/output/gl_renderer.cc
+++ b/cc/output/gl_renderer.cc
@@ -81,6 +81,23 @@ Float4 UVTransform(const TextureDrawQuad* quad) {
   return xform;
 }
 
+Float4 UVClampRect(const TextureDrawQuad* quad,
+                   const gfx::Size& texture_size,
+                   SamplerType sampler) {
+  gfx::SizeF half_texel(0.5f, 0.5f);
+  gfx::RectF uv_clamp_rect(quad->uv_top_left.x(), quad->uv_top_left.y(),
+                           quad->uv_bottom_right.x() - quad->uv_top_left.x(),
+                           quad->uv_bottom_right.y() - quad->uv_top_left.y());
+  if (sampler != SAMPLER_TYPE_2D_RECT) {
+    half_texel.Scale(1.f / texture_size.width(), 1.f / texture_size.height());
+  } else {
+    uv_clamp_rect.Scale(texture_size.width(), texture_size.height());
+  }
+  uv_clamp_rect.Inset(half_texel.width(), half_texel.height());
+  return {{uv_clamp_rect.x(), uv_clamp_rect.y(), uv_clamp_rect.right(),
+           uv_clamp_rect.bottom()}};
+}
+
 Float4 PremultipliedColor(SkColor color) {
   const float factor = 1.0f / 255.0f;
   const float alpha = SkColorGetA(color) * factor;
@@ -2485,8 +2502,19 @@ void GLRenderer::DrawStreamVideoQuad(const DrawingFrame* frame,
 
   gl_->Uniform1i(program->fragment_shader().sampler_location(), 0);
 
-  SetShaderOpacity(quad->shared_quad_state->opacity,
-                   program->fragment_shader().alpha_location());
+  // Prevent texture bleeding issue.
+  {
+    gfx::Size texture_size = lock.size();
+    gfx::SizeF half_texel(0.5f / texture_size.width(),
+                          0.5f / texture_size.height());
+    gfx::Vector2dF uv = quad->matrix.Scale2d();
+    gfx::RectF tex_clamp_rect(0, 0, uv.x(), uv.y());
+    tex_clamp_rect.Inset(half_texel.width(), half_texel.height());
+    gl_->Uniform4f(program->fragment_shader().tex_clamp_rect_location(),
+                   tex_clamp_rect.x(), tex_clamp_rect.y(),
+                   tex_clamp_rect.right(), tex_clamp_rect.bottom());
+  }
+
   if (!clip_region) {
     DrawQuadGeometry(frame->projection_matrix,
                      quad->shared_quad_state->quad_to_target_transform,
@@ -2529,9 +2557,12 @@ struct TexTransformTextureProgramBinding : TextureProgramBinding {
     tex_transform_location = program->vertex_shader().tex_transform_location();
     vertex_opacity_location =
         program->vertex_shader().vertex_opacity_location();
+    tex_clamp_rect_location =
+        program->fragment_shader().tex_clamp_rect_location();
   }
   int tex_transform_location;
   int vertex_opacity_location;
+  int tex_clamp_rect_location;
 };
 
 void GLRenderer::FlushTextureQuadCache(BoundGeometry flush_binding) {
@@ -2572,6 +2603,12 @@ void GLRenderer::FlushTextureQuadCache(BoundGeometry flush_binding) {
                   static_cast<int>(draw_cache_.uv_xform_data.size()),
                   reinterpret_cast<float*>(&draw_cache_.uv_xform_data.front()));
 
+  // Prevent texture bleeding issue.
+  gl_->Uniform4fv(
+      draw_cache_.tex_clamp_rect_location,
+      static_cast<int>(draw_cache_.tex_clamp_rect_data.size()),
+      reinterpret_cast<float*>(&draw_cache_.tex_clamp_rect_data.front()));
+
   if (draw_cache_.background_color != SK_ColorTRANSPARENT) {
     Float4 background_color = PremultipliedColor(draw_cache_.background_color);
     gl_->Uniform4fv(draw_cache_.background_color_location, 1,
@@ -2615,6 +2652,7 @@ void GLRenderer::FlushTextureQuadCache(BoundGeometry flush_binding) {
   // Clear the cache.
   draw_cache_.program_id = -1;
   draw_cache_.uv_xform_data.resize(0);
+  draw_cache_.tex_clamp_rect_data.resize(0);
   draw_cache_.vertex_opacity_data.resize(0);
   draw_cache_.matrix_data.resize(0);
 
@@ -2679,6 +2717,7 @@ void GLRenderer::EnqueueTextureQuad(const DrawingFrame* frame,
     draw_cache_.background_color = quad->background_color;
 
     draw_cache_.uv_xform_location = binding.tex_transform_location;
+    draw_cache_.tex_clamp_rect_location = binding.tex_clamp_rect_location;
     draw_cache_.background_color_location = binding.background_color_location;
     draw_cache_.vertex_opacity_location = binding.vertex_opacity_location;
     draw_cache_.matrix_location = binding.matrix_location;
@@ -2699,6 +2738,14 @@ void GLRenderer::EnqueueTextureQuad(const DrawingFrame* frame,
   }
   draw_cache_.uv_xform_data.push_back(uv_transform);
 
+  // Prevent texture bleeding issue.
+  if (draw_cache_.tex_clamp_rect_location != -1) {
+    // VideoLayerImpl always set background color to transparent.
+    DCHECK(quad->background_color == SK_ColorTRANSPARENT);
+    Float4 tex_clamp_rect = UVClampRect(quad, lock.size(), sampler);
+    draw_cache_.tex_clamp_rect_data.push_back(tex_clamp_rect);
+  }
+
   // Generate the vertex opacity
   const float opacity = quad->shared_quad_state->opacity;
   draw_cache_.vertex_opacity_data.push_back(quad->vertex_opacity[0] * opacity);