Adding drawable to CRD andorid and iOS gl rendering pipeline.

remoting/client/display/gl_canvas.h

Index: remoting/client/display/gl_canvas.h
diff --git a/remoting/client/display/gl_canvas.h b/remoting/client/display/gl_canvas.h
index 975d79bc9f981b0b691fa91ca846b11b877be416..a7b8d60e46802986e42eecb68ee9e1e1ac87c49b 100644
--- a/remoting/client/display/gl_canvas.h
+++ b/remoting/client/display/gl_canvas.h
@@ -9,6 +9,7 @@
 
 #include "base/macros.h"
 #include "base/threading/thread_checker.h"
+#include "remoting/client/display/canvas.h"
 #include "remoting/client/display/sys_opengl.h"
 
 namespace remoting {
@@ -17,12 +18,14 @@ namespace remoting {
 // draw textures on the canvas.
 // Must be constructed after the OpenGL surface is created and destroyed before
 // the surface is destroyed.
-class GlCanvas {
+class GlCanvas : public Canvas {
  public:
   // gl_version: version number of the OpenGL ES context. Either 2 or 3.
   GlCanvas(int gl_version);
 
-  ~GlCanvas();
+  ~GlCanvas() override;
+
+  void Clear() override;
 
   // Sets the transformation matrix. This matrix defines how the canvas should
   // be shown on the view.
@@ -37,10 +40,10 @@ class GlCanvas {
   // For a typical transformation matrix such that m1=m3=m6=m7=0 and m8=1, m0
   // and m4 defines the scaling factor of the canvas and m2 and m5 defines the
   // offset of the upper-left corner in pixel.
-  void SetTransformationMatrix(const std::array<float, 9>& matrix);
+  void SetTransformationMatrix(const std::array<float, 9>& matrix) override;
 
   // Sets the size of the view in pixels.
-  void SetViewSize(int width, int height);
+  void SetViewSize(int width, int height) override;
 
   // Draws the texture on the canvas. Nothing will happen if
   // SetNormalizedTransformation() has not been called.
@@ -55,14 +58,14 @@ class GlCanvas {
   void DrawTexture(int texture_id,
                    GLuint texture_handle,
                    GLuint vertex_buffer,
-                   float alpha_multiplier);
+                   float alpha_multiplier) override;
 
   // Returns the version number of current OpenGL ES context. Either 2 or 3.
-  int GetGlVersion() const;
+  int GetVersion() const override;
 
   // Returns the maximum texture resolution limitation. Neither the width nor
   // the height of the texture can exceed this limitation.
-  int GetMaxTextureSize() const;
+  int GetMaxTextureSize() const override;
 
  private:
   int gl_version_;