Hack to fix Mac64 build break from r169638.

This part of the source is fairly fragile. I had to temporarily add a
direct include to WebFrame.h because typedefs cannot be forward
declared. Unfortunately, this causes IntSize.h to be included before
Cocoa. Since Cocoa.h can set NSGEOMETRY_TYPES_SAME_AS_CGGEOMETRY_TYPES,
this can cause build failures with conflicting typedef redefinitions of
NSRect. To hack around this, we temporarily move the Cocoa.h include to
the header as well.

BUG=355268

Review URL: https://codereview.chromium.org/209663002

git-svn-id: svn://svn.chromium.org/blink/trunk@169826 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Use wrapper_configuration consistently in bindings

Currently the bindings overuse WrapperConfiguration::Dependent.
This changes it to use WrapperConfiguration::Independent
unless Dependent is actually needed, by computing it once
in the interface context.
(Fixes one FIXME and removes some hard-coding.)

This is split off as 1/2 bindings-only change from:
Implement ImageData constructors.
https://codereview.chromium.org/196343032/

BUG=345503
TBR=haraken

Review URL: https://codereview.chromium.org/199633014

git-svn-id: svn://svn.chromium.org/blink/trunk@169827 bbb929c8-8fbe-4397-9dbb-9b2b20218538