Check if internal_format is valid for GenerateMipmap().

gpu/command_buffer/service/texture_manager.h

Index: gpu/command_buffer/service/texture_manager.h
diff --git a/gpu/command_buffer/service/texture_manager.h b/gpu/command_buffer/service/texture_manager.h
index 5a07d99ee79ce48e3e25029797bbca5c3a1b9ade..723f0fb4fc34451021beee4f376262b028160433 100644
--- a/gpu/command_buffer/service/texture_manager.h
+++ b/gpu/command_buffer/service/texture_manager.h
@@ -344,7 +344,7 @@ class GPU_EXPORT Texture {
       const FeatureInfo* feature_info, GLenum pname, GLfloat param);
 
   // Makes each of the mip levels as though they were generated.
-  bool MarkMipmapsGenerated(const FeatureInfo* feature_info);
+  void MarkMipmapsGenerated(const FeatureInfo* feature_info);
 
   bool NeedsMips() const {
     return min_filter_ != GL_NEAREST && min_filter_ != GL_LINEAR;
@@ -756,8 +756,7 @@ class GPU_EXPORT TextureManager : public base::trace_event::MemoryDumpProvider {
       TextureRef* ref, GLenum pname, GLfloat param);
 
   // Makes each of the mip levels as though they were generated.
-  // Returns false if that's not allowed for the given texture.
-  bool MarkMipmapsGenerated(TextureRef* ref);
+  void MarkMipmapsGenerated(TextureRef* ref);
 
   // Clears any uncleared renderable levels.
   bool ClearRenderableLevels(GLES2Decoder* decoder, TextureRef* ref);