[Pinch-to-zoom] Moved scale factor into PinchViewport

public/web/WebView.h

Index: public/web/WebView.h
diff --git a/public/web/WebView.h b/public/web/WebView.h
index 7c9a0d1228f953201958385705f2c07530f8d730..8262ec3e31a9eb5e416750a637bc8053a957d199 100644
--- a/public/web/WebView.h
+++ b/public/web/WebView.h
@@ -64,6 +64,7 @@ struct WebActiveWheelFlingParameters;
 struct WebMediaPlayerAction;
 struct WebPluginAction;
 struct WebPoint;
+struct WebFloatPoint;
 struct WebWindowFeatures;
 
 class WebView : public WebWidget {
@@ -230,19 +231,37 @@ public:
     // page scale set in the page's viewport meta tag.
     virtual void setInitialPageScaleOverride(float) = 0;
 
+    // TODO: Remove once all uses are converted to the "PinchViewport" methods below.
     // Gets the scale factor of the page, where 1.0 is the normal size, > 1.0
     // is scaled up, < 1.0 is scaled down.
     virtual float pageScaleFactor() const = 0;
 
-    // Scales the page and the scroll offset by a given factor, while ensuring
-    // that the new scroll position does not go beyond the edge of the page.
-    virtual void setPageScaleFactorPreservingScrollOffset(float) = 0;
-
+    // TODO: Remove once all uses are converted to the "PinchViewport" methods below.
     // Scales a page by a factor of scaleFactor and then sets a scroll position to (x, y).
     // setPageScaleFactor() magnifies and shrinks a page without affecting layout.
     // On the other hand, zooming affects layout of the page.
     virtual void setPageScaleFactor(float scaleFactor, const WebPoint& origin) = 0;
 
+    // TODO: Remove once all uses are converted to the "PinchViewport" methods below.
+    // Temporary to keep old style pinch viewport working while we gradually bring up
+    // virtual viewport pinch.
+    virtual void setMainFrameScrollOffset(const WebPoint& origin) = 0;
+
+    // Scales the page without affecting layout by using the pinch-to-zoom viewport.
+    virtual void setPinchViewportScaleFactor(float) = 0;

[aelias_OOO_until_Jul13, 2014/04/10 16:23:49]

On second thought, I would suggest that you not change the name of
"PageScaleFactor" here.  The most important thing is to keep the name of the
value consistent across the codebase which means you're going down the path of
renaming a lot more stuff like the entire PageScaleAnimation and
PageScaleConstraintsSet classes.  But those things don't even have to do with
pinch so it's not clear that's an improvement.

Ultimately I think readers of this code do need a basic understanding of the
difference between page scale and full-page zoom.  If they don't, they'll still
be confused regardless of what we name things.  And once they do, the code is
unambiguous because we consistently use "scale" for the first one and "zoom" for
the other.  So I don't think this is urgent or obviously an improvement given
the other concern about not everything being pinch.

Moreover I think you should focus on shipping the behavior change and spend your
time on a big mechanical rename right now.  This would be easier when Blink is
merged with Chromium, anyway.

+
+    // Gets the scale factor set on the pinch-to-zoom viewport.
+    virtual float pinchViewportScaleFactor() const = 0;
+
+    // Sets the offset of the pinch-to-zoom viewport within the main frame, in
+    // partial CSS pixels. The offset will be clamped so the pinch viewport
+    // stays within the frame's bounds.
+    virtual void setPinchViewportOffset(const WebFloatPoint&) = 0;
+
+    // Gets the pinch viewport's current offset within the page's main frame,
+    // in partial CSS pixels.
+    virtual WebFloatPoint pinchViewportOffset() const = 0;
+
     // PageScaleFactor will be force-clamped between minPageScale and maxPageScale
     // (and these values will persist until setPageScaleFactorLimits is called
     // again).