Add common GLFence::IsSupported() check

ui/gl/gl_fence.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_fence.h"
 
 #include "base/compiler_specific.h"
 #include "ui/gl/gl_bindings.h"
 #include "ui/gl/gl_context.h"
+#include "ui/gl/gl_gl_api_implementation.h"
 #include "ui/gl/gl_version_info.h"
 
+namespace gfx {
+
 namespace {
 
-class GLFenceNVFence: public gfx::GLFence {
+class GLFenceNVFence: public GLFence {
  public:
   GLFenceNVFence(bool flush) {
     // What if either of these GL calls fails? TestFenceNV will return true.
     // See spec:
     // http://www.opengl.org/registry/specs/NV/fence.txt
     //
     // What should happen if TestFenceNV is called for a name before SetFenceNV
     // is called?
     //     We generate an INVALID_OPERATION error, and return TRUE.
     //     This follows the semantics for texture object names before
     //     they are bound, in that they acquire their state upon binding.
     //     We will arbitrarily return TRUE for consistency.
     glGenFencesNV(1, &fence_);
     glSetFenceNV(fence_, GL_ALL_COMPLETED_NV);
     if (flush) {
       glFlush();
     } else {
-      flush_event_ = gfx::GLContext::GetCurrent()->SignalFlush();
+      flush_event_ = GLContext::GetCurrent()->SignalFlush();
     }
   }
 
   virtual bool HasCompleted() OVERRIDE {
     return !!glTestFenceNV(fence_);
   }
 
   virtual void ClientWait() OVERRIDE {
     if (!flush_event_ || flush_event_->IsSignaled()) {
       glFinishFenceNV(fence_);
     } else {
       LOG(ERROR) << "Trying to wait for uncommitted fence. Skipping...";
     }
   }
 
   virtual void ServerWait() OVERRIDE {
     ClientWait();
   }
 
  private:
   virtual ~GLFenceNVFence() {
     glDeleteFencesNV(1, &fence_);
   }
 
   GLuint fence_;
-  scoped_refptr<gfx::GLContext::FlushEvent> flush_event_;
+  scoped_refptr<GLContext::FlushEvent> flush_event_;
 };
 
-class GLFenceARBSync: public gfx::GLFence {
+class GLFenceARBSync: public GLFence {
  public:
   GLFenceARBSync(bool flush) {
     sync_ = glFenceSync(GL_SYNC_GPU_COMMANDS_COMPLETE, 0);
     if (flush) {
       glFlush();
     } else {
-      flush_event_ = gfx::GLContext::GetCurrent()->SignalFlush();
+      flush_event_ = GLContext::GetCurrent()->SignalFlush();
     }
   }
 
   virtual bool HasCompleted() OVERRIDE {
     // Handle the case where FenceSync failed.
     if (!sync_)
       return true;
 
     // We could potentially use glGetSynciv here, but it doesn't work
     // on OSX 10.7 (always says the fence is not signaled yet).
@@ skipping 16 matching lines @@
       LOG(ERROR) << "Trying to wait for uncommitted fence. Skipping...";
     }
   }
 
  private:
   virtual ~GLFenceARBSync() {
     glDeleteSync(sync_);
   }
 
   GLsync sync_;
-  scoped_refptr<gfx::GLContext::FlushEvent> flush_event_;
+  scoped_refptr<GLContext::FlushEvent> flush_event_;
 };
 
 #if !defined(OS_MACOSX)
-class EGLFenceSync : public gfx::GLFence {
+class EGLFenceSync : public GLFence {
  public:
   EGLFenceSync(bool flush) {
     display_ = eglGetCurrentDisplay();
     sync_ = eglCreateSyncKHR(display_, EGL_SYNC_FENCE_KHR, NULL);
     if (flush) {
       glFlush();
     } else {
-      flush_event_ = gfx::GLContext::GetCurrent()->SignalFlush();
+      flush_event_ = GLContext::GetCurrent()->SignalFlush();
     }
   }
 
   virtual bool HasCompleted() OVERRIDE {
     EGLint value = 0;
     eglGetSyncAttribKHR(display_, sync_, EGL_SYNC_STATUS_KHR, &value);
     DCHECK(value == EGL_SIGNALED_KHR || value == EGL_UNSIGNALED_KHR);
     return !value || value == EGL_SIGNALED_KHR;
   }
 
@@ skipping 17 matching lines @@
   }
 
 
  private:
   virtual ~EGLFenceSync() {
     eglDestroySyncKHR(display_, sync_);
   }
 
   EGLSyncKHR sync_;
   EGLDisplay display_;
-  scoped_refptr<gfx::GLContext::FlushEvent> flush_event_;
+  scoped_refptr<GLContext::FlushEvent> flush_event_;
 };
 #endif // !OS_MACOSX
 
 // static
-gfx::GLFence* CreateFence(bool flush) {
-  DCHECK(gfx::GLContext::GetCurrent())
+GLFence* CreateFence(bool flush) {
+  DCHECK(GLContext::GetCurrent())
       << "Trying to create fence with no context";
 
+  scoped_ptr<GLFence> fence;
   // Prefer ARB_sync which supports server-side wait.
-  if (gfx::g_driver_gl.ext.b_GL_ARB_sync ||
-      gfx::GLContext::GetCurrent()->GetVersionInfo()->is_es3)
-    return new GLFenceARBSync(flush);
+  if (g_driver_gl.ext.b_GL_ARB_sync ||
+      GetGLVersionInfo()->is_es3) {
+    fence.reset(new GLFenceARBSync(flush));
 #if !defined(OS_MACOSX)
-  if (gfx::g_driver_egl.ext.b_EGL_KHR_fence_sync)
-    return new EGLFenceSync(flush);
+  } else if (g_driver_egl.ext.b_EGL_KHR_fence_sync) {
+    fence.reset(new EGLFenceSync(flush));
 #endif
-  if (gfx::g_driver_gl.ext.b_GL_NV_fence)
-    return new GLFenceNVFence(flush);
-  return NULL;
+  } else if (g_driver_gl.ext.b_GL_NV_fence) {
+    fence.reset(new GLFenceNVFence(flush));
+  }
+
+  DCHECK(!!fence.get() == GLFence::IsSupported());

[reveman, 2014/06/17 00:50:05]

DCHECK_EQ?

+  return fence.release();
 }
 
 }  // namespace
 
-namespace gfx {
-
 GLFence::GLFence() {
 }
 
 GLFence::~GLFence() {
 }
 
+bool GLFence::IsSupported() {
+  DCHECK(GetGLVersionInfo());
+  return g_driver_gl.ext.b_GL_ARB_sync || GetGLVersionInfo()->is_es3 ||
+#if !defined(OS_MACOSX)
+         g_driver_egl.ext.b_EGL_KHR_fence_sync ||
+#endif
+         g_driver_gl.ext.b_GL_NV_fence;
+}
+
 GLFence* GLFence::Create() {
   return CreateFence(true);
 }
 
 GLFence* GLFence::CreateWithoutFlush() {
   return CreateFence(false);
 }
 
 }  // namespace gfx