Move members of HTMLPlugInImageElement to HTMLPlugInElement, part 4.

Move members of HTMLPlugInImageElement to HTMLPlugInElement, part 4.

This CL moves the following member functions:
 - allowedToLoadFrameURL()
 - wouldLoadAsNetscapePlugin()
 - createRenderer()
 - willRecalcStyle()
 - finishParsingChildren()

Note: We should move setHasCustomStyleCallbacks() call in the constructor
for willRecalcStyle().

Also, this CL remove member functions without implementations,
swapRendererTimerFired() and restartSimilarPlugIns().

This is a part of a task to merge HTMLPlugInImageELement into HTMLPlugInElement.
Only HTMLPlugInImageElement inherits from HTMLPlugInElement.

BUG=309978
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=160401

[Hajime Morrita, 2013-10-24 01:09:06]

lgtm. It might be nice to have R= line in the CL description so that log reader
can see who is a good person to contact.

[commit-bot: I haz the power, 2013-10-24 01:17:45]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/tkent@chromium.org/38453002/1

[commit-bot: I haz the power, 2013-10-24 01:22:33]

Change committed as 160401