Take GL version and extensions correctly into account when binding functions

ui/gl/gl_implementation.h

 // Copyright (c) 2012 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 UI_GL_GL_IMPLEMENTATION_H_
 #define UI_GL_GL_IMPLEMENTATION_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 24 matching lines @@
 
 void GetAllowedGLImplementations(std::vector<GLImplementation>* impls);
 
 #if defined(OS_WIN)
 typedef void* (WINAPI *GLGetProcAddressProc)(const char* name);
 #else
 typedef void* (*GLGetProcAddressProc)(const char* name);
 #endif
 
 // Initialize a particular GL implementation.
-GL_EXPORT bool InitializeGLBindings(GLImplementation implementation);
+GL_EXPORT bool InitializeStaticGLBindings(GLImplementation implementation);
 
-// Initialize extension function bindings for a GL implementation.
-GL_EXPORT bool InitializeGLExtensionBindings(GLImplementation implementation,
+// Initialize function bindings that depend on the context for a GL
+// implementation.
+GL_EXPORT bool InitializeDynamicGLBindings(GLImplementation implementation,
     GLContext* context);
 
 // Initialize Debug logging wrappers for GL bindings.
 void InitializeDebugGLBindings();
 
 GL_EXPORT void ClearGLBindings();
 
 // Set the current GL implementation.
 GL_EXPORT void SetGLImplementation(GLImplementation implementation);
 
@@ skipping 12 matching lines @@
 
 // Add a native library to those searched for GL entry points.
 void AddGLNativeLibrary(base::NativeLibrary library);
 
 // Unloads all native libraries.
 void UnloadGLNativeLibraries();
 
 // Set an additional function that will be called to find GL entry points.
 void SetGLGetProcAddressProc(GLGetProcAddressProc proc);
 
-// Find a core (non-extension) entry point in the current GL implementation. On
-// EGL based implementations core entry points will not be queried through
-// GLGetProcAddressProc.
-void* GetGLCoreProcAddress(const char* name);
-
-// Find an entry point in the current GL implementation.
+// Find an entry point in the current GL implementation. Note that the function
+// may return garbage if an unsupported function is queried. This is the case at
+// least with spec-compliant eglGetProcAddress and glxGetProcAddress and when
+// querying functions from the EGL library supplied by Android, which contains

[no sievers, 2013/12/05 20:51:57]

Well, it's not really garbage it returns on Android but the correct entry point,
since we always bind again libGLESv2.so (and not the driver). If the driver does
not have the entry point and you call into the platform library it will log a
warning that the function is unsupported.

[oetuaho, 2013/12/09 17:17:07]

Yeah, I'll re-word the comment to make this clear.

+// stubs for unsupported functions known to that Android version.
 void* GetGLProcAddress(const char* name);
 
 // Return information about the GL window system binding implementation (e.g.,
 // EGL, GLX, WGL). Returns true if the information was retrieved successfully.
 GL_EXPORT bool GetGLWindowSystemBindingInfo(GLWindowSystemBindingInfo* info);
 
 }  // namespace gfx
 
 #endif  // UI_GL_GL_IMPLEMENTATION_H_