Introduce GLStubApi

ui/gl/gl_gl_api_implementation.cc

 // 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.
 
 #include "ui/gl/gl_gl_api_implementation.h"
 
 #include <vector>
 
 #include "base/command_line.h"
 #include "base/stl_util.h"
@@ skipping 10 matching lines @@
 
 // The GL Api being used. This could be g_real_gl or gl_trace_gl
 static GLApi* g_gl = NULL;
 // A GL Api that calls directly into the driver.
 static RealGLApi* g_real_gl = NULL;
 // A GL Api that does nothing but warn about illegal GL calls without a context
 // current.
 static NoContextGLApi* g_no_context_gl = NULL;
 // A GL Api that calls TRACE and then calls another GL api.
 static TraceGLApi* g_trace_gl = NULL;
+// The GL Api being used for stub contexts. If null, g_gl is used instead.
+static GLApi* g_stub_gl = NULL;
 // GL version used when initializing dynamic bindings.
 static GLVersionInfo* g_version_info = NULL;
 
 namespace {
 
 static inline GLenum GetInternalFormat(GLenum internal_format) {
   if (GetGLImplementation() != kGLImplementationEGLGLES2) {
     if (internal_format == GL_BGRA_EXT || internal_format == GL_BGRA8_EXT)
       return GL_RGBA8;
   }
@@ skipping 332 matching lines @@
 }
 
 void SetGLApi(GLApi* api) {
   g_current_gl_context_tls->Set(api);
 }
 
 void SetGLToRealGLApi() {
   SetGLApi(g_gl);
 }
 
+void SetGLToStubGLApi() {
+  SetGLApi(g_stub_gl ? g_stub_gl : g_gl);

[no sievers, 2016/07/11 22:42:41]

What uses GLContextStub in a way that this has to fall back to the real API?

[piman, 2016/07/11 23:57:27]

The mock bindings use RealGLApi, but hooking GetProcAddress to return a
trampoline function that calls into the MockGLInterface. I suspect it would be
possible to change the mock bindings to also hook directly at the GLApi level
instead (a little saner), but there is so much test code that relies on the
current hookup that I think it wouldn't be productive to try to migrate it
wholesale.

+}
+
 void SetGLApiToNoContext() {
   SetGLApi(g_no_context_gl);
 }
 
+void SetStubGLApi(GLApi* api) {
+  g_stub_gl = api;
+}
+
 const GLVersionInfo* GetGLVersionInfo() {
   return g_version_info;
 }
 
 void InitializeDynamicGLBindingsGL(GLContext* context) {
   if (g_version_info)
     return;
   g_real_gl->InitializeFilteredExtensions();
   g_driver_gl.InitializeCustomDynamicBindings(context);
   DCHECK(context && context->IsCurrent(NULL) && !g_version_info);
@@ skipping 26 matching lines @@
   }
   if (g_trace_gl) {
     delete g_trace_gl;
     g_trace_gl = NULL;
   }
   if (g_no_context_gl) {
     delete g_no_context_gl;
     g_no_context_gl = NULL;
   }
   g_gl = NULL;
+  g_stub_gl = NULL;
   g_driver_gl.ClearBindings();
   if (g_current_gl_context_tls) {
     delete g_current_gl_context_tls;
     g_current_gl_context_tls = NULL;
   }
   if (g_version_info) {
     delete g_version_info;
     g_version_info = NULL;
   }
 }
@@ skipping 109 matching lines @@
 TraceGLApi::~TraceGLApi() {
 }
 
 NoContextGLApi::NoContextGLApi() {
 }
 
 NoContextGLApi::~NoContextGLApi() {
 }
 
 }  // namespace gl