Photo Picker Dialog: Add caching for the decoded images.

chrome/android/java/res/values/dimens.xml

Index: chrome/android/java/res/values/dimens.xml
diff --git a/chrome/android/java/res/values/dimens.xml b/chrome/android/java/res/values/dimens.xml
index 342678df69d4027a2d19270c48ab4be9702bd6cc..df7b1cfa0fd937abbc26066766f8384a104a065f 100644
--- a/chrome/android/java/res/values/dimens.xml
+++ b/chrome/android/java/res/values/dimens.xml
@@ -374,6 +374,7 @@
     <dimen name="photo_picker_label_gap">10dp</dimen>
     <dimen name="photo_picker_tile_min_size">100dp</dimen>
     <dimen name="photo_picker_tile_gap">4dp</dimen>
+    <dimen name="photo_picker_grainy_thumbnail_size">12dp</dimen>
 
     <!-- Account chooser dialog dimensions -->
     <dimen name="account_chooser_dialog_margin">24dp</dimen>
@@ -471,7 +472,7 @@
     <!-- Context Menu Dimensions -->
     <dimen name="context_menu_header_image_min_size">56dp</dimen>
     <dimen name="context_menu_header_image_max_size">56dp</dimen>
-    
+
     <!-- Divider Dimensions -->
     <dimen name="divider_height">1dp</dimen>