Revert of Use the pinch viewport offset for tap disambiguation.

Revert of Use the pinch viewport offset for tap disambiguation. (patchset #3 id:40001 of https://codereview.chromium.org/584893004/)

Reason for revert:
Makes webkit_unit_tests fail on Android:

[  FAILED  ] 1 test, listed below:
[  FAILED  ] WebFrameTest.DisambiguationPopupPinchViewport

 1 FAILED TEST
C   79.116s Main  ********************************************************************************
C   79.116s Main  Detailed Logs
C   79.116s Main  ********************************************************************************
C   79.119s Main  [FAIL] WebFrameTest.DisambiguationPopupPinchViewport:
C   79.119s Main  ../../third_party/WebKit/Source/web/tests/WebFrameTest.cpp:4413: Failure
C   79.119s Main  Value of: (frame->view()->scrollPosition()).y()
C   79.119s Main    Actual: 0
C   79.119s Main  Expected: (IntPoint(0, 400)).y()
C   79.119s Main  Which is: 400
C   79.119s Main  ../../third_party/WebKit/Source/web/tests/WebFrameTest.cpp:4434: Failure
C   79.119s Main  Value of: client.triggered()
C   79.119s Main    Actual: false
C   79.119s Main  Expected: true
C   79.120s Main  ********************************************************************************
C   79.120s Main  Summary
C   79.120s Main  ********************************************************************************
C   79.126s Main  [==========] 1467 tests ran.
C   79.126s Main  [  PASSED  ] 1466 tests.
C   79.126s Main  [  FAILED  ] 1 test, listed below:
C   79.126s Main  [  FAILED  ] WebFrameTest.DisambiguationPopupPinchViewport
C   79.126s Main  
C   79.126s Main  1 FAILED TEST
C   79.127s Main  ********************************************************************************

Original issue's description:
> Use the pinch viewport offset for tap disambiguation.
> 
> Account for the pinch vieport offset in the touch rectangle calculation
> and pass the offset to the client. The client needs the touch rectangle
> relative to both the main frame and to the screen.
> 
> This change is part 1 of 2 (part 2 is chromium side change https://codereview.chromium.org/595693002).
> 
> BUG=370470
> 
> Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=182534

TBR=aelias@chromium.org,bokan@chromium.org,jamesr@chromium.org,timav@google.com,timav@chromium.org
NOTREECHECKS=true
NOTRY=true
BUG=370470
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=182579

[Mads Ager (chromium), 2014-09-24 10:25:37]

Created Revert of Use the pinch viewport offset for tap disambiguation.

[commit-bot: I haz the power, 2014-09-24 10:26:43]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/602583003/1

[commit-bot: I haz the power, 2014-09-24 10:27:31]

Committed patchset #1 (id:1) as 182579