Workaround for Intel 6xxx clear to 0/1 bug

ui/gl/gl_gl_api_implementation.h

Index: ui/gl/gl_gl_api_implementation.h
diff --git a/ui/gl/gl_gl_api_implementation.h b/ui/gl/gl_gl_api_implementation.h
index ba66b85ddf639241beb3916df95e0cae6acc2418..002db564e5d9a23d2d82aeafbd2dbb8c88889aae 100644
--- a/ui/gl/gl_gl_api_implementation.h
+++ b/ui/gl/gl_gl_api_implementation.h
@@ -19,6 +19,7 @@ class CommandLine;
 namespace gl {
 
 struct GLVersionInfo;
+struct GLWorkarounds;
 
 GL_EXPORT void InitializeStaticGLBindingsGL();
 GL_EXPORT void ClearBindingsGL();
@@ -103,6 +104,10 @@ class GL_EXPORT RealGLApi : public GLApiBase {
                                           GLsizei height) override;
 
   void glClearFn(GLbitfield mask) override;
+  void glClearColorFn(GLclampf red,
+                      GLclampf green,
+                      GLclampf blue,
+                      GLclampf alpha) override;
   void glDrawArraysFn(GLenum mode, GLint first, GLsizei count) override;
   void glDrawElementsFn(GLenum mode,
                         GLsizei count,
@@ -113,6 +118,7 @@ class GL_EXPORT RealGLApi : public GLApiBase {
   void glDepthRangeFn(GLclampd z_near, GLclampd z_far) override;
 
   void InitializeFilteredExtensions();
+  void setGLWorkarounds(GLWorkarounds* workarounds);
   void set_version(std::unique_ptr<GLVersionInfo> version);
 
  private:
@@ -121,6 +127,7 @@ class GL_EXPORT RealGLApi : public GLApiBase {
   std::vector<std::string> filtered_exts_;
   std::string filtered_exts_str_;
 
+  GLWorkarounds* gl_workarounds_;

[Zhenyao Mo, 2017/07/11 18:24:48]

Let's make it GLWorkarounds gl_workarounds_ instead.  Copying is trivia, and we
don't have to worry about lifetime.

[jiajia.qin, 2017/07/12 05:01:00]

Ack. To make it GLWorkarounds gl_workarounds_ instead of GLWorkaronds*, I have
to put the definition of struct of GLWorkarounds in a separate file because that
the original definition of GLworkarounds is in gl_context.h and gl_context.h
includes gl_gl_api_implementation.h.

   std::unique_ptr<GLVersionInfo> version_;
 
 #if DCHECK_IS_ON()