Refactor GL bindings so there is no global GLApi or DriverGL.

ui/gl/gl_context.h

Index: ui/gl/gl_context.h
diff --git a/ui/gl/gl_context.h b/ui/gl/gl_context.h
index 542940c7683894bb857e311f97bbb53cf0102583..893b0de0d243e135ad774f4ec572fd703ec09a68 100644
--- a/ui/gl/gl_context.h
+++ b/ui/gl/gl_context.h
@@ -28,10 +28,16 @@ class GLContextVirtual;
 
 namespace gl {
 
+struct CurrentGL;
+class DebugGLApi;
+struct DriverGL;
+class GLApi;
 class GLSurface;
 class GPUTiming;
 class GPUTimingClient;
 struct GLVersionInfo;
+class RealGLApi;
+class TraceGLApi;
 
 struct GLContextAttribs {
   GpuPreference gpu_preference = PreferIntegratedGpu;
@@ -137,9 +143,17 @@ class GL_EXPORT GLContext : public base::RefCounted<GLContext> {
   // Returns a helper structure to convert YUV textures to RGB textures.
   virtual YUVToRGBConverter* GetYUVToRGBConverter();
 
+  // Get the CurrentGL object for this context containing the driver, version
+  // and API.
+  CurrentGL* GetCurrentGL();
+
  protected:
   virtual ~GLContext();
 
+  // Create the GLApi for this context using the provided driver. Creates a
+  // RealGLApi by default.
+  virtual GLApi* CreateGLApi(DriverGL* driver);
+
   // Will release the current context when going out of scope, unless canceled.
   class ScopedReleaseCurrent {
    public:
@@ -153,7 +167,7 @@ class GL_EXPORT GLContext : public base::RefCounted<GLContext> {
   };
 
   // Sets the GL api to the real hardware API (vs the VirtualAPI)
-  static void SetRealGLApi();
+  void BindGLApi();
   virtual void SetCurrent(GLSurface* surface);
 
   // Initialize function pointers to functions where the bound version depends
@@ -172,6 +186,19 @@ class GL_EXPORT GLContext : public base::RefCounted<GLContext> {
   // For GetRealCurrent.
   friend class gpu::GLContextVirtual;
 
+  std::unique_ptr<GLVersionInfo> GenerateGLVersionInfo();
+
+  bool static_bindings_initialized_;
+  bool dynamic_bindings_initialized_;
+  std::unique_ptr<DriverGL> driver_gl_;
+  std::unique_ptr<GLApi> gl_api_;
+  std::unique_ptr<TraceGLApi> trace_gl_api_;
+  std::unique_ptr<DebugGLApi> debug_gl_api_;
+  std::unique_ptr<CurrentGL> current_gl_;
+
+  // Copy of the real API (if one was created) for dynamic initialization
+  RealGLApi* real_gl_api_ = nullptr;
+
   scoped_refptr<GLShareGroup> share_group_;
   GLContext* current_virtual_context_;
   bool state_dirtied_externally_;