Revert of remove more redundant calls to drawingContext (patchset #3 of https://codereview.chromium.org/503263002/)

Reason for revert:
this is breaking builds widely:
http://build.chromium.org/p/chromium.webkit/builders/WebKit%20Mac%20Builder%20%28dbg%29/builds/91456/steps/compile/logs/stdio
http://build.chromium.org/p/chromium.webkit/builders/WebKit%20Win%20Builder%20%28dbg%29/builds/53993/steps/compile/logs/stdio

Original issue's description:
> remove more redundant calls to drawingContext
> 
> To call CanvasRenderingContext2D::drawingContext is not cheap. This function 
> checks whether the context is lost, whether the imagebuffer surface is valid.
> 
> Data from Linux perf tool for Canvas2D benchmarks (FishIETank, SpeedReading, 
> Galactic, GM3 vector and bitmap...) shows that rotate/translate/scale/clip 
> are frequently called per frame. However, these APIs call drawingContext twice. 
> As a result, drawingContext costs 2% ~ 7% of the whole render process in these 
> benchmarks. 
> 
> This simple CL makes rotate/translate/scale/clip/... pass GraphicsContext 
> to realizeSaves() if these callers can. The CL removes redundant calls of 
> drawingContext() to improve performance.
> 
> BUG=
> 
> Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=180985

TBR=junov@chromium.org,tomhudson@chromium.org,yunchao.he@intel.com
NOTREECHECKS=true
NOTRY=true
BUG=

Review URL: https://codereview.chromium.org/489243003

git-svn-id: svn://svn.chromium.org/blink/trunk@180986 bbb929c8-8fbe-4397-9dbb-9b2b20218538