Revert 210138 "Perform glReadPixels with PBOs in the gpu, if PBO..."

> Perform glReadPixels with PBOs in the gpu, if PBOs are available.
> Make GL_ASYNC_READ_PIXELS_COMPLETED_CHROMIUM wait for readpixel transfers.
> PLEASE NOTE: glMapBuffer does not wait for the readpixels transfer to complete anymore.
> Nobody is currently relying on that behaviour.
> Update gl_helper.cc and gl_renderer.cc to use queries.
>
> This CL is the same as https://codereview.chromium.org/16831004/
> but includes fixes for:
>   OutOfProcessPPAPITests.Graphics3D  (removed a check in query_tracker.cc)
>   GLReadbackTest.ReadPixelsWithPBO (removed, no longer a valid test)
>   GLReadbackTest.ReadPixelsWithPBOAndQuery (now uses the correct query)
>
> BUG=249925
>
> Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=209873
>
> Review URL: https://chromiumcodereview.appspot.com/18555006

TBR=hubbe@chromium.org
BUG=258169

Review URL: https://codereview.chromium.org/19029003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@211274 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 29 insertions, 51 deletions

diff --git a/content/common/gpu/client/gl_helper.cc b/content/common/gpu/client/gl_helper.cc
index 23efbdd..e4876b1 100644
--- a/content/common/gpu/client/gl_helper.cc
+++ b/content/common/gpu/client/gl_helper.cc
@@ -189,24 +189,20 @@ class GLHelper::CopyTextureToImpl :
             int32 row_stride_bytes_,
             unsigned char* pixels_,
             const base::Callback<void(bool)>& callback_)
-        : done(false),
-          size(size_),
+        : size(size_),
           bytes_per_row(bytes_per_row_),
           row_stride_bytes(row_stride_bytes_),
           pixels(pixels_),
           callback(callback_),
-          buffer(0),
-          query(0) {
+          buffer(0) {
     }
 
-    bool done;
     gfx::Size size;
     int bytes_per_row;
     int row_stride_bytes;
     unsigned char* pixels;
     base::Callback<void(bool)> callback;
     GLuint buffer;
-    WebKit::WebGLId query;
   };
 
   // A readback pipeline that also converts the data to YUV before
@@ -297,7 +293,7 @@ class GLHelper::CopyTextureToImpl :
                        GLHelper::ScalerQuality quality);
 
   static void nullcallback(bool success) {}
-  void ReadbackDone(Request *request);
+  void ReadbackDone(Request* request);
   void FinishRequest(Request* request, bool result);
   void CancelRequests();
 
@@ -385,16 +381,12 @@ void GLHelper::CopyTextureToImpl::ReadbackAsync(
                        NULL,
                        GL_STREAM_READ);
 
-  request->query = context_->createQueryEXT();
-  context_->beginQueryEXT(GL_ASYNC_READ_PIXELS_COMPLETED_CHROMIUM,
-                          request->query);
   context_->readPixels(0, 0, dst_size.width(), dst_size.height(),
                        GL_RGBA, GL_UNSIGNED_BYTE, NULL);
-  context_->endQueryEXT(GL_ASYNC_READ_PIXELS_COMPLETED_CHROMIUM);
   context_->bindBuffer(GL_PIXEL_PACK_TRANSFER_BUFFER_CHROMIUM, 0);
-  cc::SyncPointHelper::SignalQuery(
+  cc::SyncPointHelper::SignalSyncPoint(
       context_,
-      request->query,
+      context_->insertSyncPoint(),
       base::Bind(&CopyTextureToImpl::ReadbackDone, AsWeakPtr(), request));
 }
 
@@ -472,59 +464,45 @@ WebKit::WebGLId GLHelper::CopyTextureToImpl::CopyAndScaleTexture(
                       quality);
 }
 
-void GLHelper::CopyTextureToImpl::ReadbackDone(Request* finished_request) {
+void GLHelper::CopyTextureToImpl::ReadbackDone(Request* request) {
   TRACE_EVENT0("mirror",
                "GLHelper::CopyTextureToImpl::CheckReadbackFramebufferComplete");
-  finished_request->done = true;
+  DCHECK(request == request_queue_.front());
 
-  // We process transfer requests in the order they were received, regardless
-  // of the order we get the callbacks in.
-  while (!request_queue_.empty()) {
-    Request* request = request_queue_.front();
-    if (!request->done) {
-      break;
-    }
-
-    bool result = false;
-    if (request->buffer != 0) {
-      context_->bindBuffer(GL_PIXEL_PACK_TRANSFER_BUFFER_CHROMIUM,
-                           request->buffer);
-      unsigned char* data = static_cast<unsigned char *>(
-          context_->mapBufferCHROMIUM(
-              GL_PIXEL_PACK_TRANSFER_BUFFER_CHROMIUM, GL_READ_ONLY));
-      if (data) {
-        result = true;
-        if (request->bytes_per_row == request->size.width() * 4 &&
-            request->bytes_per_row == request->row_stride_bytes) {
-          memcpy(request->pixels, data, request->size.GetArea() * 4);
-        } else {
-          unsigned char* out = request->pixels;
-          for (int y = 0; y < request->size.height(); y++) {
-            memcpy(out, data, request->bytes_per_row);
-            out += request->row_stride_bytes;
-            data += request->size.width() * 4;
-          }
+  bool result = false;
+  if (request->buffer != 0) {
+    context_->bindBuffer(GL_PIXEL_PACK_TRANSFER_BUFFER_CHROMIUM,
+                         request->buffer);
+    unsigned char* data = static_cast<unsigned char *>(
+        context_->mapBufferCHROMIUM(
+            GL_PIXEL_PACK_TRANSFER_BUFFER_CHROMIUM, GL_READ_ONLY));
+    if (data) {
+      result = true;
+      if (request->bytes_per_row == request->size.width() * 4 &&
+          request->bytes_per_row == request->row_stride_bytes) {
+        memcpy(request->pixels, data, request->size.GetArea() * 4);
+      } else {
+        unsigned char* out = request->pixels;
+        for (int y = 0; y < request->size.height(); y++) {
+          memcpy(out, data, request->bytes_per_row);
+          out += request->row_stride_bytes;
+          data += request->size.width() * 4;
         }
-        context_->unmapBufferCHROMIUM(GL_PIXEL_PACK_TRANSFER_BUFFER_CHROMIUM);
       }
-      context_->bindBuffer(GL_PIXEL_PACK_TRANSFER_BUFFER_CHROMIUM, 0);
+      context_->unmapBufferCHROMIUM(GL_PIXEL_PACK_TRANSFER_BUFFER_CHROMIUM);
     }
-
-    FinishRequest(request, result);
+    context_->bindBuffer(GL_PIXEL_PACK_TRANSFER_BUFFER_CHROMIUM, 0);
   }
+
+  FinishRequest(request, result);
 }
 
 void GLHelper::CopyTextureToImpl::FinishRequest(Request* request,
                                                 bool result) {
-  TRACE_EVENT0("mirror", "GLHelper::CopyTextureToImpl::FinishRequest");
   DCHECK(request_queue_.front() == request);
   request_queue_.pop();
   request->callback.Run(result);
   ScopedFlush flush(context_);
-  if (request->query != 0) {
-    context_->deleteQueryEXT(request->query);
-    request->query = 0;
-  }
   if (request->buffer != 0) {
     context_->deleteBuffer(request->buffer);
     request->buffer = 0;