Mac: Make image dragging 162.4% more awesome.

Also needs a webkit patch to do anything ( https://bugs.webkit.org/show_bug.cgi?id=37069 ), but can be landed independently.

BUG=11457,18992
TEST=(all require the webkit patch, so this won't work yet)
http://html5demos.com/drag and http://ljouanneau.com/lab/html5/demodragdrop.html
  Dragging should show image
http://www.google.com/
  Dragging google image should show image
http://www.travelvivi.com/wp-content/uploads/2009/09/Eiffel_Tower.jpg
  Dragging image should work, drag image should be smaller than image itself
Random website
  Mark some text, drag it. Should show drag cursor and no image

Review URL: http://codereview.chromium.org/1539018

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@43631 0039d316-1c4b-4281-b951-d872f2087c98

chrome/browser/cocoa/web_drag_source.h

@@ -23,6 +23,12 @@ struct WebDropData;
   // Our drop data. Should only be initialized once.
   scoped_ptr<WebDropData> dropData_;
 
+  // The image to show as drag image. Can be nil.
+  scoped_nsobject<NSImage> dragImage_;
+
+  // The offset to draw |dragImage_| at.
+  NSPoint imageOffset_;
+
   // Our pasteboard.
   scoped_nsobject<NSPasteboard> pasteboard_;
 
@@ -41,6 +47,8 @@ struct WebDropData;
 // with data types appropriate for dropData.
 - (id)initWithContentsView:(TabContentsViewCocoa*)contentsView
                   dropData:(const WebDropData*)dropData
+                     image:(NSImage*)image
+                    offset:(NSPoint)offset
                 pasteboard:(NSPasteboard*)pboard
          dragOperationMask:(NSDragOperation)dragOperationMask;
 

chrome/browser/cocoa/web_drag_source.mm

@@ -35,16 +35,6 @@ namespace {
 // |NSURLPboardType|.
 NSString* const kNSURLTitlePboardType = @"public.url-name";
 
-// Make a drag image from the drop data.
-// TODO(viettrungluu): Move this somewhere more sensible.
-NSImage* MakeDragImage(const WebDropData* drop_data) {
-  // TODO(viettrungluu): Just a stub for now. Make it do something (see, e.g.,
-  // WebKit/WebKit/mac/Misc/WebNSViewExtras.m: |-_web_DragImageForElement:...|).
-
-  // Default to returning a generic image.
-  return nsimage_cache::ImageNamed(@"nav.pdf");
-}
-
 // Returns a filename appropriate for the drop data
 // TODO(viettrungluu): Refactor to make it common across platforms,
 // and move it somewhere sensible.
@@ -122,6 +112,8 @@ void PromiseWriterTask::Run() {
 
 - (id)initWithContentsView:(TabContentsViewCocoa*)contentsView
                   dropData:(const WebDropData*)dropData
+                     image:(NSImage*)image
+                    offset:(NSPoint)offset
                 pasteboard:(NSPasteboard*)pboard
          dragOperationMask:(NSDragOperation)dragOperationMask {
   if ((self = [super init])) {
@@ -131,6 +123,9 @@ void PromiseWriterTask::Run() {
     dropData_.reset(new WebDropData(*dropData));
     DCHECK(dropData_.get());
 
+    dragImage_.reset([image retain]);
+    imageOffset_ = offset;
+
     pasteboard_.reset([pboard retain]);
     DCHECK(pasteboard_.get());
 
@@ -225,6 +220,13 @@ void PromiseWriterTask::Run() {
                                         clickCount:1
                                           pressure:1.0];
 
+  if (dragImage_) {
+    position.x -= imageOffset_.x;
+    // Deal with Cocoa's flipped coordinate system.
+    position.y -= [dragImage_.get() size].height - imageOffset_.y;
+  }
+  // Per kwebster, offset arg is ignored, see -_web_DragImageForElement: in
+  // third_party/WebKit/WebKit/mac/Misc/WebNSViewExtras.m.
   [window dragImage:[self dragImage]
                  at:position
              offset:NSZeroSize
@@ -386,7 +388,11 @@ void PromiseWriterTask::Run() {
 }
 
 - (NSImage*)dragImage {
-  return MakeDragImage(dropData_.get());
+  if (dragImage_)
+    return dragImage_;
+
+  // Default to returning a generic image.
+  return nsimage_cache::ImageNamed(@"nav.pdf");
 }
 
 @end  // @implementation WebDragSource (Private)

chrome/browser/tab_contents/tab_contents_view_mac.mm

@@ -26,6 +26,7 @@
 #include "chrome/common/notification_type.h"
 #include "chrome/common/notification_service.h"
 #include "chrome/common/render_messages.h"
+#include "skia/ext/skia_utils_mac.h"
 #import "third_party/mozilla/include/NSPasteboard+Utils.h"
 
 using WebKit::WebDragOperation;
@@ -49,7 +50,9 @@ COMPILE_ASSERT_MATCHING_ENUM(DragOperationEvery);
 - (void)registerDragTypes;
 - (void)setCurrentDragOperation:(NSDragOperation)operation;
 - (void)startDragWithDropData:(const WebDropData&)dropData
-            dragOperationMask:(NSDragOperation)operationMask;
+            dragOperationMask:(NSDragOperation)operationMask
+                        image:(NSImage*)image
+                       offset:(NSPoint)offset;
 - (void)cancelDeferredClose;
 - (void)closeTabAfterEvent;
 @end
@@ -141,10 +144,12 @@ void TabContentsViewMac::StartDragging(
   // The drag invokes a nested event loop, arrange to continue
   // processing events.
   MessageLoop::ScopedNestableTaskAllower allow(MessageLoop::current());
-  // TODO(estade): make use of |image| and |image_offset|.
   NSDragOperation mask = static_cast<NSDragOperation>(allowed_operations);
+  NSPoint offset = NSPointFromCGPoint(image_offset.ToCGPoint());
   [cocoa_view_ startDragWithDropData:drop_data
-                   dragOperationMask:mask];
+                   dragOperationMask:mask
+                               image:gfx::SkBitmapToNSImage(image)
+                              offset:offset];
 }
 
 void TabContentsViewMac::RenderViewCreated(RenderViewHost* host) {
@@ -376,10 +381,14 @@ void TabContentsViewMac::Observe(NotificationType type,
 }
 
 - (void)startDragWithDropData:(const WebDropData&)dropData
-            dragOperationMask:(NSDragOperation)operationMask {
+            dragOperationMask:(NSDragOperation)operationMask
+                        image:(NSImage*)image
+                       offset:(NSPoint)offset {
   dragSource_.reset([[WebDragSource alloc]
           initWithContentsView:self
                       dropData:&dropData
+                         image:image
+                        offset:offset
                     pasteboard:[NSPasteboard pasteboardWithName:NSDragPboard]
              dragOperationMask:operationMask]);
   [dragSource_ startDrag];

chrome/renderer/render_view.cc

@@ -128,6 +128,8 @@
 #include "gfx/native_theme_win.h"
 #elif defined(USE_X11)
 #include "third_party/WebKit/WebKit/chromium/public/linux/WebRenderTheme.h"
+#elif defined(OS_MACOSX)
+#include "skia/ext/skia_utils_mac.h"
 #endif
 
 using appcache::WebApplicationCacheHostImpl;
@@ -1905,8 +1907,7 @@ void RenderView::startDragging(const WebDragData& data,
 #if WEBKIT_USING_SKIA
   SkBitmap bitmap(image.getSkBitmap());
 #elif WEBKIT_USING_CG
-  // Needs implementing: http://crbug.com/11457
-  SkBitmap bitmap;
+  SkBitmap bitmap = gfx::CGImageToSkBitmap(image.getCGImageRef());
 #endif
 
   Send(new ViewHostMsg_StartDragging(routing_id_,

skia/ext/skia_utils_mac.mm

@@ -168,6 +168,9 @@ SkBitmap NSImageToSkBitmap(NSImage* image, NSSize size, bool is_opaque) {
 }
 
 NSImage* SkBitmapToNSImage(const SkBitmap& skiaBitmap) {
+  if (skiaBitmap.isNull())
+    return nil;
+
   // First convert SkBitmap to CGImageRef.
   CGImageRef cgimage = SkCreateCGImageRef(skiaBitmap);