Adding drawable to CRD andorid and iOS gl rendering pipeline.

remoting/client/display/gl_canvas.cc

Index: remoting/client/display/gl_canvas.cc
diff --git a/remoting/client/display/gl_canvas.cc b/remoting/client/display/gl_canvas.cc
index 31d6b959e7dc4f20e0ded8f9f3eca18c40c65356..39f817f3f18fdd3908dec0670450526b3da9b7bc 100644
--- a/remoting/client/display/gl_canvas.cc
+++ b/remoting/client/display/gl_canvas.cc
@@ -65,6 +65,8 @@ const char kDrawTexFrag[] =
 
 namespace remoting {
 
+GlCanvas::GlCanvas() {}
+
 GlCanvas::GlCanvas(int gl_version) : gl_version_(gl_version) {
   glGetIntegerv(GL_MAX_TEXTURE_SIZE, &max_texture_size_);
 
@@ -96,6 +98,17 @@ GlCanvas::~GlCanvas() {
   glDeleteShader(fragment_shader_);
 }
 
+void GlCanvas::Clear() {
+#ifndef NDEBUG
+  // Set the background clear color to bright green for debugging purposes.
+  glClearColor(0.0f, 1.0f, 0.0f, 1.0f);
+#else
+  // Set the background clear color to black.
+  glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
+#endif
+  glClear(GL_COLOR_BUFFER_BIT);
+}
+
 void GlCanvas::SetTransformationMatrix(const std::array<float, 9>& matrix) {
   DCHECK(thread_checker_.CalledOnValidThread());
   std::array<float, 9> transposed_matrix = matrix;
@@ -137,7 +150,7 @@ void GlCanvas::DrawTexture(int texture_id,
   glBindTexture(GL_TEXTURE_2D, 0);
 }
 
-int GlCanvas::GetGlVersion() const {
+int GlCanvas::GetVersion() const {
   return gl_version_;
 }