Adding drawable to CRD andorid and iOS gl rendering pipeline.

remoting/client/display/gl_canvas.h

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef REMOTING_CLIENT_DISPLAY_GL_CANVAS_H_
 #define REMOTING_CLIENT_DISPLAY_GL_CANVAS_H_
 
 #include <array>
 
 #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 {
 
 // This class holds zoom and pan configurations of the canvas and is used to
 // 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;
 
-  // Sets the transformation matrix. This matrix defines how the canvas should
-  // be shown on the view.
-  // 3 by 3 transformation matrix, [ m0, m1, m2, m3, m4, m5, m6, m7, m8 ].
-  // The matrix will be multiplied with the positions (with projective space,
-  // (x, y, 1)) to draw the textures with the right zoom and pan configuration.
-  //
-  // | m0, m1, m2, |   | x |
-  // | m3, m4, m5, | * | y |
-  // | m6, m7, m8  |   | 1 |
-  //
-  // 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 Clear() override;
 
-  // Sets the size of the view in pixels.
-  void SetViewSize(int width, int height);
+  void SetTransformationMatrix(const std::array<float, 9>& matrix) override;
 
-  // Draws the texture on the canvas. Nothing will happen if
-  // SetNormalizedTransformation() has not been called.
-  // vertex_buffer: reference to the 2x4x2 float vertex buffer.
-  //                [ four (x, y) position of the texture vertices in pixel
-  //                              with respect to the canvas,
-  //                  four (x, y) position of the vertices in percentage
-  //                              defining the visible area of the texture ]
-  // alpha_multiplier: Will be multiplied with the alpha channel of the texture.
-  //                   Passing 1 means no change of the transparency of the
-  //                   texture.
+  void SetViewSize(int width, int height) override;
+
   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_;
 
   int max_texture_size_ = 0;
   bool transformation_set_ = false;
   bool view_size_set_ = false;
 
   // Handles.
   GLuint vertex_shader_;
   GLuint fragment_shader_;
   GLuint program_;
 
   // Locations of the corresponding shader attributes.
   GLuint transform_location_;
   GLuint view_size_location_;
   GLuint texture_location_;
   GLuint alpha_multiplier_location_;
   GLuint position_location_;
   GLuint tex_cord_location_;
 
   base::ThreadChecker thread_checker_;
 
   DISALLOW_COPY_AND_ASSIGN(GlCanvas);
 };
 
 }  // namespace remoting
 
 #endif  // REMOTING_CLIENT_DISPLAY_GL_CANVAS_H_