Revert 258122 "gpu: Allow fences to check whether a flush has oc..."

Seems to expose some GL call sites without current context.
Reverting for the time being...

BUG=355275

> gpu: Allow fences to check whether a flush has occurred
> 
> This skips waiting on a fence that was created but never committed.
> 
> BUG=352419
> 
> Review URL: https://codereview.chromium.org/197563003

TBR=sievers@chromium.org

Review URL: https://codereview.chromium.org/209853004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@258965 0039d316-1c4b-4281-b951-d872f2087c98

6 files changed, 14 insertions, 139 deletions

diff --git a/ui/gl/gl_context.cc b/ui/gl/gl_context.cc
index d2deb61..cd9a28c 100644
--- a/ui/gl/gl_context.cc
+++ b/ui/gl/gl_context.cc
@@ -26,20 +26,6 @@ base::LazyInstance<base::ThreadLocalPointer<GLContext> >::Leaky
     current_real_context_ = LAZY_INSTANCE_INITIALIZER;
 }  // namespace
 
-GLContext::FlushEvent::FlushEvent() {
-}
-
-GLContext::FlushEvent::~FlushEvent() {
-}
-
-void GLContext::FlushEvent::Signal() {
-  flag_.Set();
-}
-
-bool GLContext::FlushEvent::IsSignaled() {
-  return flag_.IsSet();
-}
-
 GLContext::GLContext(GLShareGroup* share_group) : share_group_(share_group) {
   if (!share_group_.get())
     share_group_ = new GLShareGroup;
@@ -54,13 +40,6 @@ GLContext::~GLContext() {
   }
 }
 
-scoped_refptr<GLContext::FlushEvent> GLContext::SignalFlush() {
-  DCHECK(IsCurrent(NULL));
-  scoped_refptr<FlushEvent> flush_event = new FlushEvent();
-  flush_events_.push_back(flush_event);
-  return flush_event;
-}
-
 bool GLContext::GetTotalGpuMemory(size_t* bytes) {
   DCHECK(bytes);
   *bytes = 0;
@@ -193,12 +172,6 @@ void GLContext::SetRealGLApi() {
   SetGLToRealGLApi();
 }
 
-void GLContext::OnFlush() {
-  for (size_t n = 0; n < flush_events_.size(); n++)
-    flush_events_[n]->Signal();
-  flush_events_.clear();
-}
-
 GLContextReal::GLContextReal(GLShareGroup* share_group)
     : GLContext(share_group) {}
 
diff --git a/ui/gl/gl_context.h b/ui/gl/gl_context.h
index b4a7a16..f40b1bb 100644
--- a/ui/gl/gl_context.h
+++ b/ui/gl/gl_context.h
@@ -6,12 +6,10 @@
 #define UI_GL_GL_CONTEXT_H_
 
 #include <string>
-#include <vector>
 
 #include "base/basictypes.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
-#include "base/synchronization/cancellation_flag.h"
 #include "ui/gl/gl_share_group.h"
 #include "ui/gl/gl_state_restorer.h"
 #include "ui/gl/gpu_preference.h"
@@ -34,25 +32,6 @@ class GL_EXPORT GLContext : public base::RefCounted<GLContext> {
   virtual bool Initialize(
       GLSurface* compatible_surface, GpuPreference gpu_preference) = 0;
 
-  class FlushEvent : public base::RefCountedThreadSafe<FlushEvent> {
-    public:
-      bool IsSignaled();
-
-    private:
-      friend class base::RefCountedThreadSafe<FlushEvent>;
-      friend class GLContext;
-      FlushEvent();
-      virtual ~FlushEvent();
-      void Signal();
-
-      base::CancellationFlag flag_;
-  };
-
-  // Needs to be called with this context current. It will return a FlushEvent
-  // that is initially unsignaled, but will transition to signaled after the
-  // next glFlush() or glFinish() occurs in this context.
-  scoped_refptr<FlushEvent> SignalFlush();
-
   // Destroys the GL context.
   virtual void Destroy() = 0;
 
@@ -135,9 +114,6 @@ class GL_EXPORT GLContext : public base::RefCounted<GLContext> {
   // Returns the GL renderer string. The context must be current.
   virtual std::string GetGLRenderer();
 
-  // Called when glFlush()/glFinish() is called with this context current.
-  void OnFlush();
-
  protected:
   virtual ~GLContext();
 
@@ -164,8 +140,6 @@ class GL_EXPORT GLContext : public base::RefCounted<GLContext> {
   scoped_ptr<GLStateRestorer> state_restorer_;
   scoped_ptr<GLVersionInfo> version_info_;
 
-  std::vector<scoped_refptr<FlushEvent> > flush_events_;
-
   DISALLOW_COPY_AND_ASSIGN(GLContext);
 };
 
diff --git a/ui/gl/gl_fence.cc b/ui/gl/gl_fence.cc
index 262de48..f44570e 100644
--- a/ui/gl/gl_fence.cc
+++ b/ui/gl/gl_fence.cc
@@ -25,11 +25,8 @@ class GLFenceNVFence: public gfx::GLFence {
     //     We will arbitrarily return TRUE for consistency.
     glGenFencesNV(1, &fence_);
     glSetFenceNV(fence_, GL_ALL_COMPLETED_NV);
-    if (flush) {
+    if (flush)
       glFlush();
-    } else {
-      flush_event_ = gfx::GLContext::GetCurrent()->SignalFlush();
-    }
   }
 
   virtual bool HasCompleted() OVERRIDE {
@@ -37,15 +34,11 @@ class GLFenceNVFence: public gfx::GLFence {
   }
 
   virtual void ClientWait() OVERRIDE {
-    if (!flush_event_ || flush_event_->IsSignaled()) {
-      glFinishFenceNV(fence_);
-    } else {
-      LOG(ERROR) << "Trying to wait for uncommitted fence. Skipping...";
-    }
+    glFinishFenceNV(fence_);
   }
 
   virtual void ServerWait() OVERRIDE {
-    ClientWait();
+    glFinishFenceNV(fence_);
   }
 
  private:
@@ -54,18 +47,14 @@ class GLFenceNVFence: public gfx::GLFence {
   }
 
   GLuint fence_;
-  scoped_refptr<gfx::GLContext::FlushEvent> flush_event_;
 };
 
 class GLFenceARBSync: public gfx::GLFence {
  public:
   GLFenceARBSync(bool flush) {
     sync_ = glFenceSync(GL_SYNC_GPU_COMMANDS_COMPLETE, 0);
-    if (flush) {
+    if (flush)
       glFlush();
-    } else {
-      flush_event_ = gfx::GLContext::GetCurrent()->SignalFlush();
-    }
   }
 
   virtual bool HasCompleted() OVERRIDE {
@@ -80,19 +69,11 @@ class GLFenceARBSync: public gfx::GLFence {
   }
 
   virtual void ClientWait() OVERRIDE {
-    if (!flush_event_ || flush_event_->IsSignaled()) {
-      glClientWaitSync(sync_, GL_SYNC_FLUSH_COMMANDS_BIT, GL_TIMEOUT_IGNORED);
-    } else {
-      LOG(ERROR) << "Trying to wait for uncommitted fence. Skipping...";
-    }
+    glClientWaitSync(sync_, GL_SYNC_FLUSH_COMMANDS_BIT, GL_TIMEOUT_IGNORED);
   }
 
   virtual void ServerWait() OVERRIDE {
-    if (!flush_event_ || flush_event_->IsSignaled()) {
-      glWaitSync(sync_, 0, GL_TIMEOUT_IGNORED);
-    } else {
-      LOG(ERROR) << "Trying to wait for uncommitted fence. Skipping...";
-    }
+    glWaitSync(sync_, 0, GL_TIMEOUT_IGNORED);
   }
 
  private:
@@ -101,7 +82,6 @@ class GLFenceARBSync: public gfx::GLFence {
   }
 
   GLsync sync_;
-  scoped_refptr<gfx::GLContext::FlushEvent> flush_event_;
 };
 
 #if !defined(OS_MACOSX)
@@ -110,11 +90,8 @@ class EGLFenceSync : public gfx::GLFence {
   EGLFenceSync(bool flush) {
     display_ = eglGetCurrentDisplay();
     sync_ = eglCreateSyncKHR(display_, EGL_SYNC_FENCE_KHR, NULL);
-    if (flush) {
+    if (flush)
       glFlush();
-    } else {
-      flush_event_ = gfx::GLContext::GetCurrent()->SignalFlush();
-    }
   }
 
   virtual bool HasCompleted() OVERRIDE {
@@ -125,22 +102,14 @@ class EGLFenceSync : public gfx::GLFence {
   }
 
   virtual void ClientWait() OVERRIDE {
-    if (!flush_event_ || flush_event_->IsSignaled()) {
-      EGLint flags = 0;
-      EGLTimeKHR time = EGL_FOREVER_KHR;
-      eglClientWaitSyncKHR(display_, sync_, flags, time);
-    } else {
-      LOG(ERROR) << "Trying to wait for uncommitted fence. Skipping...";
-    }
+    EGLint flags = 0;
+    EGLTimeKHR time = EGL_FOREVER_KHR;
+    eglClientWaitSyncKHR(display_, sync_, flags, time);
   }
 
   virtual void ServerWait() OVERRIDE {
-    if (!flush_event_ || flush_event_->IsSignaled()) {
-      EGLint flags = 0;
-      eglWaitSyncKHR(display_, sync_, flags);
-    } else {
-      LOG(ERROR) << "Trying to wait for uncommitted fence. Skipping...";
-    }
+    EGLint flags = 0;
+    eglWaitSyncKHR(display_, sync_, flags);
   }
 
 
@@ -151,15 +120,11 @@ class EGLFenceSync : public gfx::GLFence {
 
   EGLSyncKHR sync_;
   EGLDisplay display_;
-  scoped_refptr<gfx::GLContext::FlushEvent> flush_event_;
 };
 #endif // !OS_MACOSX
 
 // static
 gfx::GLFence* CreateFence(bool flush) {
-  DCHECK(gfx::GLContext::GetCurrent())
-      << "Trying to create fence with no context";
-
 #if !defined(OS_MACOSX)
   if (gfx::g_driver_egl.ext.b_EGL_KHR_fence_sync)
     return new EGLFenceSync(flush);
diff --git a/ui/gl/gl_fence.h b/ui/gl/gl_fence.h
index 021f345..c1967ec 100644
--- a/ui/gl/gl_fence.h
+++ b/ui/gl/gl_fence.h
@@ -16,16 +16,11 @@ class GL_EXPORT GLFence {
   virtual ~GLFence();
 
   static GLFence* Create();
-
   // Creates a fence that is not guaranteed to signal until the current context
-  // is flushed. It is illegal to call Client/ServerWait() on a fence without
-  // having explicitly called glFlush() or glFinish() in the originating
-  // context.
+  // is flushed. Use with caution.
   static GLFence* CreateWithoutFlush();
-
   virtual bool HasCompleted() = 0;
   virtual void ClientWait() = 0;
-
   // Will block the server if supported, but might fall back to blocking the
   // client.
   virtual void ServerWait() = 0;
diff --git a/ui/gl/gl_gl_api_implementation.cc b/ui/gl/gl_gl_api_implementation.cc
index 0965d91..f925f64 100644
--- a/ui/gl/gl_gl_api_implementation.cc
+++ b/ui/gl/gl_gl_api_implementation.cc
@@ -343,11 +343,6 @@ void GLApiBase::InitializeBase(DriverGL* driver) {
   driver_ = driver;
 }
 
-void GLApiBase::SignalFlush() {
-  DCHECK(GLContext::GetCurrent());
-  GLContext::GetCurrent()->OnFlush();
-}
-
 RealGLApi::RealGLApi() {
 }
 
@@ -358,16 +353,6 @@ void RealGLApi::Initialize(DriverGL* driver) {
   InitializeBase(driver);
 }
 
-void RealGLApi::glFlushFn() {
-  GLApiBase::glFlushFn();
-  GLApiBase::SignalFlush();
-}
-
-void RealGLApi::glFinishFn() {
-  GLApiBase::glFinishFn();
-  GLApiBase::SignalFlush();
-}
-
 TraceGLApi::~TraceGLApi() {
 }
 
@@ -460,14 +445,4 @@ const GLubyte* VirtualGLApi::glGetStringFn(GLenum name) {
   }
 }
 
-void VirtualGLApi::glFlushFn() {
-  GLApiBase::glFlushFn();
-  GLApiBase::SignalFlush();
-}
-
-void VirtualGLApi::glFinishFn() {
-  GLApiBase::glFinishFn();
-  GLApiBase::SignalFlush();
-}
-
 }  // namespace gfx
diff --git a/ui/gl/gl_gl_api_implementation.h b/ui/gl/gl_gl_api_implementation.h
index e764ec3..c87dbd1 100644
--- a/ui/gl/gl_gl_api_implementation.h
+++ b/ui/gl/gl_gl_api_implementation.h
@@ -41,7 +41,6 @@ class GL_EXPORT GLApiBase : public GLApi {
   GLApiBase();
   virtual ~GLApiBase();
   void InitializeBase(DriverGL* driver);
-  void SignalFlush();
 
   DriverGL* driver_;
 };
@@ -52,10 +51,6 @@ class GL_EXPORT RealGLApi : public GLApiBase {
   RealGLApi();
   virtual ~RealGLApi();
   void Initialize(DriverGL* driver);
-
- private:
-  virtual void glFinishFn() OVERRIDE;
-  virtual void glFlushFn() OVERRIDE;
 };
 
 // Inserts a TRACE for every GL call.
@@ -87,12 +82,10 @@ class GL_EXPORT VirtualGLApi : public GLApiBase {
 
   void OnReleaseVirtuallyCurrent(GLContext* virtual_context);
 
-private:
   // Overridden functions from GLApiBase
   virtual const GLubyte* glGetStringFn(GLenum name) OVERRIDE;
-  virtual void glFinishFn() OVERRIDE;
-  virtual void glFlushFn() OVERRIDE;
 
+ private:
   // The real context we're running on.
   GLContext* real_context_;