Handle mac trackpad zoom via GesturePinch events

content/browser/renderer_host/render_widget_host_view_mac.mm

 // 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 "content/browser/renderer_host/render_widget_host_view_mac.h"
 
 #import <objc/runtime.h>
 #include <QuartzCore/QuartzCore.h>
 
 #include "base/basictypes.h"
@@ skipping 70 matching lines @@
 using content::RenderViewHost;
 using content::RenderViewHostImpl;
 using content::RenderWidgetHostImpl;
 using content::RenderWidgetHostViewMac;
 using content::RenderWidgetHostViewMacEditCommandHelper;
 using content::TextInputClientMac;
 using blink::WebInputEvent;
 using blink::WebInputEventFactory;
 using blink::WebMouseEvent;
 using blink::WebMouseWheelEvent;
+using blink::WebGestureEvent;
 
 // These are not documented, so use only after checking -respondsToSelector:.
 @interface NSApplication (UndocumentedSpeechMethods)
 - (void)speakString:(NSString*)string;
 - (void)stopSpeaking:(id)sender;
 - (BOOL)isSpeaking;
 @end
 
 // Declare things that are part of the 10.7 SDK.
 #if !defined(MAC_OS_X_VERSION_10_7) || \
@@ skipping 2756 matching lines @@
   }
 
   // This is responsible for content scrolling!
   if (renderWidgetHostView_->render_widget_host_) {
     const WebMouseWheelEvent& webEvent =
         WebInputEventFactory::mouseWheelEvent(event, self);
     renderWidgetHostView_->render_widget_host_->ForwardWheelEvent(webEvent);
   }
 }
 
+// Called repeatedly during a pinch gesture, with incremental change values.
+- (void)magnifyWithEvent:(NSEvent*)event {
+  if (renderWidgetHostView_->render_widget_host_) {
+    // Send a GesturePinchUpdate event.
+    // Note that we don't attempt to bracket these by GesturePinchBegin/End (or
+    // GestureSrollBegin/End) as is done for touchscreen.  Keeping track of when
+    // a pinch is active would take a little more work here, and we don't need
+    // it for anything yet.
+    const WebGestureEvent& webEvent =
+        WebInputEventFactory::gestureEvent(event, self);
+    renderWidgetHostView_->render_widget_host_->ForwardGestureEvent(webEvent);
+  }
+}
+
 - (void)viewWillMoveToWindow:(NSWindow*)newWindow {
   NSWindow* oldWindow = [self window];
 
   // We're messing with the window, so do this to ensure no flashes. This one
   // prevents a flash when the current tab is closed.
   if (!renderWidgetHostView_->use_core_animation_)
     [oldWindow disableScreenUpdatesUntilFlush];
 
   NSNotificationCenter* notificationCenter =
       [NSNotificationCenter defaultCenter];
@@ skipping 1364 matching lines @@
                                    CGColorGetConstantColor(kCGColorWhite));
     CGContextFillRect(context, clipRect);
   }
 }
 
 - (void)disableRendering {
   renderWidgetHostView_ = NULL;
 }
 
 @end  // implementation SoftwareLayer