Back CAOpenGLLayers by CGL contexts instead of NSGL contexts

Change CompositingIOSurfaceContext to have a separate path
for creating a CGLContextObj directly, rather than creating a
NSOpenGLContext and using its CGLContextObj. Add asserts
to prevent trying to grab the NSOpenGLContext when using
CoreAnimation.

Change the CAOpenGLLayer to create the CGLContextObj at
creation, and pass a retained pointer to it and its pixel format
when requested, and allow the superclass to handle the release
of the pixel format and context. This matches the behavior in
WebKit.

Change DisplayLinkMac to call CVDisplayLinkRelease instead
of CFRelease because here is no documentation that CFRelease
may be used with a CVDisplayLink.

BUG=245900

Review URL: https://codereview.chromium.org/131453012

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@249398 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 13 insertions, 55 deletions

diff --git a/content/browser/renderer_host/compositing_iosurface_layer_mac.mm b/content/browser/renderer_host/compositing_iosurface_layer_mac.mm
index 7417e29..b05ffe2 100644
--- a/content/browser/renderer_host/compositing_iosurface_layer_mac.mm
+++ b/content/browser/renderer_host/compositing_iosurface_layer_mac.mm
@@ -23,6 +23,9 @@
 - (id)initWithRenderWidgetHostViewMac:(content::RenderWidgetHostViewMac*)r {
   if (self = [super init]) {
     renderWidgetHostView_ = r;
+    context_ = content::CompositingIOSurfaceContext::Get(
+        content::CompositingIOSurfaceContext::kOffscreenContextWindowNumber);
+    DCHECK(context_);
 
     ScopedCAActionDisabler disabler;
     [self setBackgroundColor:CGColorGetConstantColor(kCGColorWhite)];
@@ -64,60 +67,15 @@
 // The remaining methods implement the CAOpenGLLayer interface.
 
 - (CGLPixelFormatObj)copyCGLPixelFormatForDisplayMask:(uint32_t)mask {
-  std::vector<CGLPixelFormatAttribute> attribs;
-  attribs.push_back(kCGLPFADepthSize);
-  attribs.push_back(static_cast<CGLPixelFormatAttribute>(0));
-  if (ui::GpuSwitchingManager::GetInstance()->SupportsDualGpus()) {
-    attribs.push_back(kCGLPFAAllowOfflineRenderers);
-    attribs.push_back(static_cast<CGLPixelFormatAttribute>(1));
-  }
-  attribs.push_back(static_cast<CGLPixelFormatAttribute>(0));
-
-  GLint number_virtual_screens = 0;
-  CGLPixelFormatObj pixel_format = NULL;
-  CGLError error = CGLChoosePixelFormat(
-      &attribs.front(), &pixel_format, &number_virtual_screens);
-  if (error != kCGLNoError) {
-    LOG(ERROR) << "Failed to create pixel format for layer.";
-    CHECK(0);
-    return nil;
-  }
-  return pixel_format;
-}
-
-- (void)releaseCGLPixelFormat:(CGLPixelFormatObj)pixelFormat {
-  if (!pixelFormat) {
-    CHECK(0);
-  }
-
-  CGLReleasePixelFormat(pixelFormat);
+  if (!context_)
+    return [super copyCGLPixelFormatForDisplayMask:mask];
+  return CGLRetainPixelFormat(CGLGetPixelFormat(context_->cgl_context()));
 }
 
 - (CGLContextObj)copyCGLContextForPixelFormat:(CGLPixelFormatObj)pixelFormat {
-  if (!renderWidgetHostView_) {
-    CHECK(0);
-    LOG(ERROR) << "Cannot create layer context because there is no host.";
-    return nil;
-  }
-
-  context_ = renderWidgetHostView_->compositing_iosurface_context_;
-  if (!context_) {
-    CHECK(0);
-    LOG(ERROR) << "Cannot create layer context because host has no context.";
-    return nil;
-  }
-
-  return context_->cgl_context();
-}
-
-- (void)releaseCGLContext:(CGLContextObj)glContext {
-  if (!context_) {
-    CHECK(0);
-    return;
-  }
-
-  DCHECK(glContext == context_->cgl_context());
-  context_ = nil;
+  if (!context_)
+    return [super copyCGLContextForPixelFormat:pixelFormat];
+  return CGLRetainContext(context_->cgl_context());
 }
 
 - (void)drawInCGLContext:(CGLContextObj)glContext
@@ -126,15 +84,15 @@
              displayTime:(const CVTimeStamp*)timeStamp {
   TRACE_EVENT0("browser", "CompositingIOSurfaceLayer::drawInCGLContext");
 
-  if (!context_.get() || !renderWidgetHostView_ ||
+  if (!context_ ||
+      (context_ && context_->cgl_context() != glContext) ||
+      !renderWidgetHostView_ ||
       !renderWidgetHostView_->compositing_iosurface_) {
     glClearColor(1, 1, 1, 1);
     glClear(GL_COLOR_BUFFER_BIT);
     return;
   }
 
-  DCHECK(glContext == context_->cgl_context());
-
   // Cache a copy of renderWidgetHostView_ because it may be reset if
   // a software frame is received in GetBackingStore.
   content::RenderWidgetHostViewMac* cached_view = renderWidgetHostView_;
@@ -147,6 +105,7 @@
     cached_view->about_to_validate_and_paint_ = true;
     (void)cached_view->render_widget_host_->GetBackingStore(true);
     cached_view->about_to_validate_and_paint_ = false;
+    CGLSetCurrentContext(glContext);
   }
 
   // If a transition to software mode has occurred, this layer should be
@@ -159,7 +118,6 @@
   if ([self respondsToSelector:(@selector(contentsScale))])
     window_scale_factor = [self contentsScale];
 
-  CGLSetCurrentContext(glContext);
   if (!renderWidgetHostView_->compositing_iosurface_->DrawIOSurface(
         context_,
         window_rect,