[Remoting Android] Make EglThreadContext create OpenGL ES 3 context

remoting/client/jni/egl_thread_context.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_JNI_EGL_THREAD_CONTEXT_H_
 #define REMOTING_CLIENT_JNI_EGL_THREAD_CONTEXT_H_
 
 #include <EGL/egl.h>
 
 #include "base/macros.h"
 #include "base/threading/thread_checker.h"
 
 namespace remoting {
 
-// Establishes an EGL-OpenGL|ES2 context on current thread. Must be constructed,
-// used, and deleted on single thread (i.e. the display thread). Each thread can
-// have no more than one EglThreadContext.
-//
-// An example use case:
-// class DisplayHandler {
-//   void OnSurfaceCreated(ANativeWindow* surface) {
-//     context_.BindToWindow(surface);
-//   }
-//   void OnSurfaceDestroyed() {
-//     context_.BindToWindow(nullptr);
-//   }
-//   EglThreadContext context_;
-// };
+// Establishes an EGL-OpenGL|ES 2 (if 3 is not supported) or 3 (backward
+// compatible with 2) context on current thread. Must be constructed, used, and
+// deleted on single thread (i.e. the display thread). Each thread can have no
+// more than one EglThreadContext.
 class EglThreadContext {
  public:
+  enum ClientVersion {
+    CLIENT_VERSION_UNKNOWN = 0,
+    CLIENT_VERSION_ES_2 = 2,
+    CLIENT_VERSION_ES_3 = 3
+  };
+
   EglThreadContext();
   ~EglThreadContext();
 
   // Creates a surface on the given window and binds the context to the surface.
   // Unbinds |window| last bound if |window| is NULL.
   // EGLNativeWindowType is platform specific. E.g. ANativeWindow* on Android.
   void BindToWindow(EGLNativeWindowType window);
 
-  // Returns true IFF the context is bound to a window (i.e. current surface is
-  // not NULL).
+  // Returns true if the context is bound to a window (i.e. current surface is
+  // not NULL), false otherwise.

[Lambros, 2016/07/23 01:50:13]

"false otherwise" is not needed; see
https://google.github.io/styleguide/cppguide.html#Function_Comments
(search for "false otherwise").

[Yuwei, 2016/07/25 17:59:41]

Done.

   bool IsWindowBound() const;
 
-  // Posts EGL surface buffer to the window being bound. Window must be bound
-  // before calling this function.
-  void SwapBuffers();
+  // Posts EGL surface buffer to the window being bound.
+  // Returns true if the buffer is successfully swapped, false otherwise.

[Lambros, 2016/07/23 01:50:13]

Same here.

[Yuwei, 2016/07/25 17:59:41]

Done.

+  bool SwapBuffers();
+
+  // Returns the current OpenGL ES client version of the EGL context. It will be
+  // either 2 or 3.
+  ClientVersion client_version() const {
+    return client_version_;
+  }
 
  private:
+  // Creates an EGLContext with given |renderable_type| and |client_version|.
+  // |renderable_type| and |client_version| must match with each other.
+  // E.g. renderable_type = EGL_OPENGL_ES3_BIT,
+  //      client_version = CLIENT_VERSION_ES_3.
+  bool CreateContextWithClientVersion(int renderable_type,
+                                      ClientVersion client_version);
+
   EGLDisplay display_ = EGL_NO_DISPLAY;
   EGLConfig config_ = nullptr;
   EGLSurface surface_ = EGL_NO_SURFACE;
   EGLContext context_ = EGL_NO_CONTEXT;
+  ClientVersion client_version_ = CLIENT_VERSION_UNKNOWN;
 
   base::ThreadChecker thread_checker_;
 
   DISALLOW_COPY_AND_ASSIGN(EglThreadContext);
 };
 
 }  // namespace remoting
 
 #endif  // REMOTING_CLIENT_JNI_EGL_THREAD_CONTEXT_H_