Add a path to use CALayers to display content

content/browser/renderer_host/compositing_iosurface_layer_mac.mm

+// Copyright (c) 2013 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 "content/browser/renderer_host/compositing_iosurface_layer_mac.h"
+
+#include <CoreFoundation/CoreFoundation.h>
+
+#include "base/mac/sdk_forward_declarations.h"
+#include "content/browser/renderer_host/render_widget_host_view_mac.h"
+#include "content/browser/renderer_host/compositing_iosurface_context_mac.h"
+#include "content/browser/renderer_host/compositing_iosurface_mac.h"
+#include "ui/base/cocoa/animation_utils.h"
+#include "ui/gfx/size_conversions.h"
+
+@implementation CompositingIOSurfaceLayer
+
+@synthesize context = context_;
+
+- (id)initWithRenderWidgetHostViewMac:(content::RenderWidgetHostViewMac*)r {
+  if (self = [super init]) {
+    renderWidgetHostView_ = r;
+
+    ScopedCAActionDisabler disabler;
+    [self setAutoresizingMask:kCALayerWidthSizable | kCALayerHeightSizable];
+    [self setContentsGravity:kCAGravityTopLeft];
+    [self setFrame:NSRectToCGRect(
+        [renderWidgetHostView_->cocoa_view() bounds])];
+    [self setNeedsDisplay];
+    [self updateScaleFactor];
+    [[renderWidgetHostView_->cocoa_view() layer] addSublayer:self];
+  }
+  return self;
+}
+
+- (BOOL)ensureContext {
+  if (context_)
+    return YES;
+
+  if (!renderWidgetHostView_)
+    return NO;
+
+  if (renderWidgetHostView_->compositing_iosurface_)
+    context_ = renderWidgetHostView_->compositing_iosurface_->context();
+
+  if (!context_) {
+    context_ = content::CompositingIOSurfaceContext::Get(
+        renderWidgetHostView_->window_number());
+  }
+
+  return context_ ? YES : NO;
+}
+
+- (void)updateScaleFactor {
+  if (!renderWidgetHostView_ ||
+      ![self respondsToSelector:(@selector(contentsScale))] ||
+      ![self respondsToSelector:(@selector(setContentsScale:))])
+    return;
+
+  float current_scale_factor = [self contentsScale];
+  float new_scale_factor = current_scale_factor;
+  if (renderWidgetHostView_->compositing_iosurface_) {
+    new_scale_factor =
+        renderWidgetHostView_->compositing_iosurface_->scale_factor();
+  }
+
+  if (new_scale_factor == current_scale_factor)
+    return;
+
+  ScopedCAActionDisabler disabler;
+  [self setContentsScale:new_scale_factor];
+}
+
+- (void)disableCompositing{
+  ScopedCAActionDisabler disabler;
+  [self removeFromSuperlayer];
+  renderWidgetHostView_ = nil;
+}
+
+// The remaining methods implement the CAOpenGLLayer interface.
+
+- (CGLContextObj)copyCGLContextForPixelFormat:(CGLPixelFormatObj)pixelFormat {
+  if ([self ensureContext])
+    return context_->cgl_context();
+  return nil;
+}
+
+- (void)releaseCGLContext:(CGLContextObj)glContext {
+  if (!context_)
+    return;
+
+  DCHECK(glContext == context_->cgl_context());
+  context_ = nil;
+}
+
+- (void)drawInCGLContext:(CGLContextObj)glContext
+             pixelFormat:(CGLPixelFormatObj)pixelFormat
+            forLayerTime:(CFTimeInterval)timeInterval
+             displayTime:(const CVTimeStamp*)timeStamp {
+  if (!context_ || !renderWidgetHostView_ ||
+      !renderWidgetHostView_->compositing_iosurface_) {
+    glClearColor(1, 1, 1, 1);
+    glClear(GL_COLOR_BUFFER_BIT);
+    return;
+  }
+
+  DCHECK(glContext == context_->cgl_context());
+
+  gfx::Size window_size([self frame].size);
+  float window_scale_factor = 1.f;
+  if ([self respondsToSelector:(@selector(contentsScale))])
+    window_scale_factor = [self contentsScale];
+
+  renderWidgetHostView_->compositing_iosurface_->DrawIOSurface(
+    window_size,
+    window_scale_factor,
+    renderWidgetHostView_->frame_subscriber(),
+    true);
+
+  renderWidgetHostView_->AckPendingSwapBuffers();
+}
+
+@end