Remove magnifyScaleAroundAnchor method

This method was used by the old Mac trackpad pinch zoom path. In
https://crrev.com/297980d7a0e33b44dce6c727d7016345a80e33fa we removed
this special case for Mac and started relying on sending GesturePinch
events for processing in the compositor, just like touchscreen pinch.
This method is now unused.

Bug: 787924
Change-Id: I91737b4abe160830ed7068c2634b678304cc99f7
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1534349
Commit-Queue: David Bokan <bokan@chromium.org>
Reviewed-by: Kevin McNee <mcnee@chromium.org>
Cr-Commit-Position: refs/heads/master@{#643613}

third_party/blink/renderer/core/frame/visual_viewport.cc

@@ -520,36 +520,6 @@ bool VisualViewport::DidSetScaleOrLocation(float scale,
   return true;
 }
 
-bool VisualViewport::MagnifyScaleAroundAnchor(float magnify_delta,
-                                              const FloatPoint& anchor) {
-  const float old_page_scale = Scale();
-  const float new_page_scale =
-      GetPage().GetChromeClient().ClampPageScaleFactorToLimits(magnify_delta *
-                                                               old_page_scale);
-  if (new_page_scale == old_page_scale)
-    return false;
-  if (!MainFrame() || !MainFrame()->View())
-    return false;
-
-  // Keep the center-of-pinch anchor in a stable position over the course
-  // of the magnify.
-  // TODO(bokan): Looks like we call into setScaleAndLocation with infinity for
-  // the location so it seems either old or newPageScale is invalid.
-  // crbug.com/702771.
-  FloatPoint anchor_at_old_scale = anchor.ScaledBy(1.f / old_page_scale);
-  FloatPoint anchor_at_new_scale = anchor.ScaledBy(1.f / new_page_scale);
-  FloatSize anchor_delta = anchor_at_old_scale - anchor_at_new_scale;
-
-  // First try to use the anchor's delta to scroll the LocalFrameView.
-  FloatSize anchor_delta_unused_by_scroll = anchor_delta;
-
-  // Manually bubble any remaining anchor delta up to the visual viewport.
-  FloatPoint new_location(FloatPoint(GetScrollOffset()) +
-                          anchor_delta_unused_by_scroll);
-  SetScaleAndLocation(new_page_scale, new_location);
-  return true;
-}
-
 void VisualViewport::CreateLayerTree() {
   if (RuntimeEnabledFeatures::CompositeAfterPaintEnabled())
     return;

third_party/blink/renderer/core/frame/visual_viewport.h

@@ -153,11 +153,6 @@ class CORE_EXPORT VisualViewport final
   void SetScale(float);
   float Scale() const { return scale_; }
 
-  // Update scale factor, magnifying or minifying by magnifyDelta, centered
-  // around the point specified by anchor in window coordinates. Returns false
-  // if page scale factor is left unchanged.
-  bool MagnifyScaleAroundAnchor(float magnify_delta, const FloatPoint& anchor);
-
   // Convert the given rect in the main LocalFrameView's coordinates into a rect
   // in the viewport. The given and returned rects are in CSS pixels, meaning
   // scale isn't applied.

third_party/blink/renderer/core/testing/internals.cc

@@ -2475,14 +2475,6 @@ void Internals::setPageScaleFactorLimits(float min_scale_factor,
   page->SetDefaultPageScaleLimits(min_scale_factor, max_scale_factor);
 }
 
-bool Internals::magnifyScaleAroundAnchor(float scale_factor, float x, float y) {
-  if (!GetFrame())
-    return false;
-
-  return GetFrame()->GetPage()->GetVisualViewport().MagnifyScaleAroundAnchor(
-      scale_factor, FloatPoint(x, y));
-}
-
 void Internals::setIsCursorVisible(Document* document,
                                    bool is_visible,
                                    ExceptionState& exception_state) {

third_party/blink/renderer/core/testing/internals.h

@@ -392,8 +392,6 @@ class Internals final : public ScriptWrappable {
                                 float max_scale_factor,
                                 ExceptionState&);
 
-  bool magnifyScaleAroundAnchor(float factor, float x, float y);
-
   void setIsCursorVisible(Document*, bool, ExceptionState&);
 
   String effectivePreload(HTMLMediaElement*);

third_party/blink/renderer/core/testing/internals.idl

@@ -341,8 +341,6 @@
 
     void setVisualViewportOffset(long x, long y);
 
-    boolean magnifyScaleAroundAnchor(float offset, float x, float y);
-
     boolean isUseCounted(Document document, unsigned long feature);
     boolean isCSSPropertyUseCounted(Document document, DOMString propertyName);
     boolean isAnimatedCSSPropertyUseCounted(Document document, DOMString propertyName);