Add test data for dynamic CLD.

This is necessary in order to allow browser tests to run correctly when using
CLD in dynamic mode (either from an external file or via the component
updater). This change is being split apart from the actual tests that use it
because the CLD data file is too large to commit via the CQ and, as a result,
must be dcommit'ed.

BUG=367239
R=rmcilroy@chromium.org

Review URL: https://codereview.chromium.org/289313004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@271372 0039d316-1c4b-4281-b951-d872f2087c98

chrome/test/data/cld2_component/160/manifest.json

+{
+  "manifest_version": 2,
+  "name": "CLD2 Data",
+  "description": "Compact Language Detector 2 (CLD2) data for Chrome",
+  "minimum_chrome_version": "36",
+  "version": "160",
+  "platforms": [
+    {
+      "sub_package_path": "_platform_specific/all/"
+    }
+  ]
+}
\ No newline at end of file

chrome/test/data/cld2_component/README.chromium

+This directory contains a static copy of the contents of the CLD2 CRX file.
+The ID of the extension (as well as other relevant information) can be found
+in the following file:
+  src/chrome/browser/component_updater/cld_component_installer.cc 
+
+In general there should be little need to modify the data here. CLD2 updates
+are rare and consist of incremental improvements to language detection
+accuracy. All such updates are expected to be backwards-compatible from CLD2
+revision 160 onwards, which was the initial version to be checked in. Any
+future format-breaking changes are likely to result in a "CLD3".
+
+For the sake of maintainability and clarity of purpose, the subdirectory that
+contains the CRX extract is named for the version that is contained within it.
+This mimics the behavior of the component updater and makes it obvious at a
+glance which version of the CRX is checked in here; if you DO update the
+content here, make sure to make a new directory and update the constant in the
+test utilities class:
+  src/chrome/browser/translate/translate_browser_test_utils.cc
+
+If backwards compatibility is required, you'll have to add tests to try with
+both the old version and the new.
+
+For more information please refer to:
+  src/third_party/cld_2/README.chromium
+