cros: Enhanced Clipboard

This seems large, but a lot of this is boiler
plate, moved files, or vector icons.

This feature is a productivity experiment.
The basics are:
 - Copy some things, per usual.
 - Press search + v to see a small menu showing
   previously copied things.
 - Select one of the previously copied things,
   the result will be that it is pasted into the
   active window.

Known issues:
 - Some webapps render their text input in an
   IFrame, and we cannot know where the caret is.
    - https://crbug.com/1099930

Metrics and more tests will be in the next CL.

Bug: 1095209, 1099309
Change-Id: Icb8a44cec5ad038ddfdb2889c71fa89065ac8138
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2274463
Commit-Queue: Alex Newcomer <[email protected]>
Reviewed-by: Darwin Huang <[email protected]>
Reviewed-by: Xiyuan Xia <[email protected]>
Cr-Commit-Position: refs/heads/master@{#787350}
diff --git a/chrome/browser/flag_descriptions.cc b/chrome/browser/flag_descriptions.cc
index 5e12edf9..974e1f1 100644
--- a/chrome/browser/flag_descriptions.cc
+++ b/chrome/browser/flag_descriptions.cc
@@ -3603,6 +3603,14 @@
     "with multi-display-overview-and-split-view (otherwise you are likely to "
     "get a crash).";
 
+const char kEnhancedClipboardName[] =
+    "Productivity Experiment: Enable Enhanced Clipboard";
+const char kEnhancedClipboardDescription[] =
+    "Enables an experimental clipboard history which aims to reduce context "
+    "switching. After copying to the clipboard, press search + v to show the "
+    "history. Selecting something from the menu will result in a paste to the "
+    "active window.";
+
 const char kMultiDisplayOverviewAndSplitViewName[] =
     "Enable multi-display overview and split view.";
 const char kMultiDisplayOverviewAndSplitViewDescription[] =