Tidy up error reporting for calling-constructor-as-function.

Introduce an ExceptionMessage helper for emitting the desired error
message when calling a constructor as a function & have the IDL compiler
generate calls to it.

At the same time, make 'detail' a required argument to all 'failedToXX'
methods on ExceptionMessage -- better if the caller is required to
supply meaningful info.

R=nbarth@chromium.org,haraken@chromium.org
BUG=

Review URL: https://codereview.chromium.org/211333004

git-svn-id: svn://svn.chromium.org/blink/trunk@170037 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Pack StyleColor members in StyleRareInheritedData tighter to save memory

Since StyleColor stores the color value (32-bit RGBA) plus a single flag,
it is a bit inefficient.  In particular when multiple StyleColor objects
are members of another object, there will be a lot of unnecessary padding.

This padding can be avoided by storing the color value and the flag as
separate members of the containing structure, which allows the flags to
be packed into a bitfield.

The actual saving from this change, measured in a 64-bit Linux build, is
20 bytes per StyleRareInheritedData object.

BUG=356124

Review URL: https://codereview.chromium.org/196103013

git-svn-id: svn://svn.chromium.org/blink/trunk@170038 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Convert line breaks from DOS to UNIX style.

git-svn-id: svn://svn.chromium.org/blink/trunk@170039 bbb929c8-8fbe-4397-9dbb-9b2b20218538