Revert of Avoid redundant initialization of GraphicsContextState. (https://codereview.chromium.org/303613002/)

Reason for revert:
This change is the cause of a
leak in PhishingDOMFeatureExtractorTest.ScriptAndImageFeatures
under LSAN. See
http://build.chromium.org/p/chromium.memory/builders/Linux%20ASan%20LSan%20Tests%20%281%29/builds/2642/steps/browser_tests/logs/ScriptAndImageFeatures

Original issue's description:
> Avoid redundant initialization of GraphicsContextState.
> 
> When creating a new GraphicsContextState the constructor initializes the state
> with various default values. In GraphicsContext::realizePaintState we immediately
> overwrite these values after creation. This patch adds a copy constructor to
> GraphicsContextState to avoid that.
> 
> Even though this seems like a clear win, the benefits are not visible when
> profiling. Looks like the overhead of the redundant initialization is
> not very large. Still seems worth fixing though.
> 
> BUG=377687
> 
> Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=174985

TBR=schenney@chromium.org,fmalita@chromium.org,dominikg@chromium.org
NOTREECHECKS=true
NOTRY=true
BUG=377687

Review URL: https://codereview.chromium.org/303403006

git-svn-id: svn://svn.chromium.org/blink/trunk@175159 bbb929c8-8fbe-4397-9dbb-9b2b20218538