-. Add new variables for multi dll build:    1. multi_dll_build: whether or not to build multi dll version.    2. component: used for library that can be built as DLL.         component is set to shared_library if multi_dll_build==1,         in other cases, it is set to "<(library)". -. Fix win_use_allocator_shim comments and some MSVCRT related settings.
-. Add new variables for multi dll build:
   1. multi_dll_build: whether or not to build multi dll version.
   2. component: used for library that can be built as DLL.
        component is set to shared_library if multi_dll_build==1,
        in other cases, it is set to "<(library)".
-. Fix win_use_allocator_shim comments and some MSVCRT related settings.

Note: this patch just adds new variables. They are not ready to use yet.

R=darin
BUG=46311
TEST=none

Review URL: http://codereview.chromium.org/2836013

git-svn-id: de016e52bd170d2d4f2344f9bf92d50478b649e0@50362 0039d316-1c4b-4281-b951-d872f2087c98

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