Improve mobile device rotation behavior.

Source/WebKit/chromium/src/ViewportAnchor.h

Index: Source/WebKit/chromium/src/ViewportAnchor.h
diff --git a/Source/WebKit/chromium/public/WebUserGestureToken.h b/Source/WebKit/chromium/src/ViewportAnchor.h
similarity index 55%
copy from Source/WebKit/chromium/public/WebUserGestureToken.h
copy to Source/WebKit/chromium/src/ViewportAnchor.h
index e81b6262b819b9fbbabb6659f94e648a9096105c..b3797e3a0317961cf4f426adec66982f8c1f8cce 100644
--- a/Source/WebKit/chromium/public/WebUserGestureToken.h
+++ b/Source/WebKit/chromium/src/ViewportAnchor.h
@@ -28,46 +28,53 @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-#ifndef WebUserGestureToken_h
-#define WebUserGestureToken_h
+#ifndef ViewportAnchor_h
+#define ViewportAnchor_h
 
-#include "../../../Platform/chromium/public/WebPrivatePtr.h"
+#include "FloatSize.h"
+#include "IntPoint.h"
+#include "IntRect.h"
+#include "LayoutRect.h"
+#include <wtf/RefCounted.h>
 
 namespace WebCore {
-class UserGestureToken;
+class EventHandler;
+class IntSize;
+class Node;
 }
 
 namespace WebKit {
 
-// A WebUserGestureToken allows for storing the user gesture state of the
-// currently active context and reinstantiating it later on to continue
-// processing the user gesture in case it was not consumed meanwhile.
-class WebUserGestureToken {
+// ViewportAnchor provides a way to anchor a viewport origin to a DOM node.
+// In particular, the user supplies the current viewport (in CSS coordinates)
+// and an anchor point (in view coordinates, e.g., (0, 0) == viewport origin,
+// (0.5, 0) == viewport top center). The anchor point tracks the underlying DOM
+// node; as the node moves or the view is resized, the viewport anchor maintains
+// its orientation relative to the node, and the viewport origin maintains its
+// orientation relative to the anchor.
+#if ENABLE(VIEWPORT)
+class ViewportAnchor {

[abarth-chromium, 2013/04/18 05:33:04]

This object seems to deal entirely in terms of WebCore types.  Should it be in
Core instead?

[jdduke (slow), 2013/04/18 16:20:07]

That's hard for me to say.  This was originally intended as an internal utility
class to be used only during resize operations in WebViewImpl, which is why I'd
prefer it live as close to that class as possible.  Technically, there's likely
no reason it couldn't exist in some folder within core.  

+    WTF_MAKE_NONCOPYABLE(ViewportAnchor);
 public:
-    WebUserGestureToken() { }
-    WebUserGestureToken(const WebUserGestureToken& other) { assign(other); }
-    WebUserGestureToken& operator=(const WebUserGestureToken& other)
-    {
-        assign(other);
-        return *this;
-    }
-    ~WebUserGestureToken() { reset(); }
+    explicit ViewportAnchor(WebCore::EventHandler* eventHandler);
 
-    WEBKIT_EXPORT bool hasGestures() const;
-    bool isNull() const { return m_token.isNull(); }
+    void setAnchor(const WebCore::IntRect& viewRect, const WebCore::FloatSize& anchorInViewCoords);
 
-#if WEBKIT_IMPLEMENTATION
-    explicit WebUserGestureToken(PassRefPtr<WebCore::UserGestureToken>);
-    operator PassRefPtr<WebCore::UserGestureToken>() const;
-#endif
+    WebCore::IntPoint computeOrigin(const WebCore::IntSize& currentViewSize) const;
 
 private:
-    WEBKIT_EXPORT void assign(const WebUserGestureToken&);
-    WEBKIT_EXPORT void reset();
+    WebCore::EventHandler* m_eventHandler;
 
-    WebPrivatePtr<WebCore::UserGestureToken> m_token;
+    WebCore::IntRect m_viewRect;
+
+    RefPtr<WebCore::Node> m_anchorNode;
+    WebCore::LayoutRect m_anchorNodeBounds;
+
+    WebCore::FloatSize m_anchorInViewCoords;
+    WebCore::FloatSize m_anchorInNodeCoords;
 };
+#endif // ENABLE(VIEWPORT)
 
 } // namespace WebKit
 
-#endif // WebUserGestureToken_h
+ #endif