Merge 77575 - The code to validate whether plugin dlls are 32 bit failed for ...

Merge 77575 - The code to validate whether plugin dlls are 32 bit failed for some dll's as the attempt
to create a memory mapped section with the size of the file fails with the section too large
error. As per msdn documentation we can safely pass in 0 for the file size for CreateFileMapping
and MapViewOfFile which indicates that the whole file is being mapped.

This caused some plugin dlls like acrobat reader 9 to not load in chrome.

Fixes bug http://code.google.com/p/chromium/issues/detail?id=75351

BUG=75351
TEST=manually as described in the bug.

Review URL: http://codereview.chromium.org/6661010

TBR=ananta@chromium.org

Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=77578