Componentize objc_zombie.{h,mm} and consolidate crash_keys.

Consolidate both crash_keys.{cc,h} and objc_zombie.{h,mm}} into
components/crash/core/common so that they can be used on iOS and
that there is only one component related to crash support.

Tighten the DEPS rules because stc/components/crash/core cannot
depend on src/breakpad.

BUG=522955,520968

Review URL: https://codereview.chromium.org/1358483002

Cr-Commit-Position: refs/heads/master@{#350132}
diff --git a/components/omnibox.gypi b/components/omnibox.gypi
index 1c5d027..0dfb932 100644
--- a/components/omnibox.gypi
+++ b/components/omnibox.gypi
@@ -19,7 +19,7 @@
         '../ui/gfx/gfx.gyp:gfx',
         '../url/url.gyp:url_lib',
         'bookmarks_browser',
-        'crash_keys',  # TODO(mpearson): remove once 464926 is fixed.
+        'crash_core_common',  # TODO(mpearson): remove once 464926 is fixed.
         'metrics',
         'component_metrics_proto',
         'components_resources.gyp:components_resources',