Add a command-line switch --enable-per-tile-painting.

chrome/app/generated_resources.grd

Index: chrome/app/generated_resources.grd
diff --git a/chrome/app/generated_resources.grd b/chrome/app/generated_resources.grd
index 347fa5fd158185e86a738b5fe7e63f8a73ed7301..333a46ab986f42eec762acac43e8876aea286204 100644
--- a/chrome/app/generated_resources.grd
+++ b/chrome/app/generated_resources.grd
@@ -4963,6 +4963,12 @@ Keep your key file in a safe place. You will need it to create new versions of y
       <message name="IDS_FLAGS_ENABLE_GAMEPAD_DESCRIPTION" desc="Description for the flag to enable gamepad support.">
         This API allows web applications to access data from gamepad devices connected to the system.
       </message>
+      <message name="IDS_FLAGS_PER_TILE_DRAWING_NAME" desc="Title for the flag to enable per-tile drawing">
+        Per-tile Drawing
+      </message>
+      <message name="IDS_FLAGS_PER_TILE_DRAWING_DESCRIPTION" desc="Description for the flag to enable per-tile drawing">
+        Enable per-tile drawing of page contents when compositing is enabled.
+      </message>
 
       <!-- Crashes -->
       <message name="IDS_CRASHES_TITLE" desc="Title for the chrome://crashes page.">