Android: Enable png->webp optimization for Chrome.apk

This is now safe to do for all of our apks since we don't support
JellyBean anymore.

Bug: 993342
Change-Id: I670a0d54e6b524c6fa21f712efc6214a04c74bb2
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1752102
Commit-Queue: Andrew Grieve <agrieve@chromium.org>
Reviewed-by: Theresa  <twellington@chromium.org>
Cr-Commit-Position: refs/heads/master@{#686496}

chrome/android/BUILD.gn

@@ -1606,12 +1606,6 @@ template("chrome_public_apk_or_module_tmpl") {
 
     shared_libraries = [ ":libchrome" ]
 
-    # Android supports webp transparent resources properly since API level 18,
-    # so this can only be activated for modern ones (which target API >= 21).
-    # TODO(digit): Turn this on for all builds once JellyBean support is
-    # dropped in the future.
-    png_to_webp = _is_modern && !is_java_debug
-
     # Native libraries can be loaded directly from the APK using the
     # Chromium linker. However, we disable this for J-K due to an OEM-specific
     # platform bug, where overzealous SELinux settings prevent mapping some apk
@@ -1926,6 +1920,9 @@ template("chrome_test_apk_tmpl") {
       proguard_enabled = true
       proguard_configs = [ "//chrome/android/java/apk_for_test.flags" ]
     }
+    
+    # TODO(crbug.com/993340): Update test goldens with webp versions of images.
+    png_to_webp = false
   }
 }
 

chrome/android/chrome_public_apk_tmpl.gni

@@ -173,6 +173,13 @@ template("chrome_public_common_apk_or_module_tmpl") {
       support_zh_hk = true
     }
 
+    # Android supports webp transparent resources properly since API level 18,
+    # so this can only be activated for modern ones (which target API >= 21).
+    if (!defined(png_to_webp)) {
+      png_to_webp = !is_java_debug
+    }
+
+    # Removes metadata needed for Resources.getIdentifier("resource_name").
     strip_resource_names = !is_java_debug
 
     # TODO(753402): enable once aapt2>=3.6.0 and bundletool>0.9.0 are rolled in.
@@ -449,7 +456,6 @@ template("monochrome_public_common_apk_or_module_tmpl") {
       if (is_monochrome) {
         proguard_configs += [ "//android_webview/apk/java/proguard.flags" ]
       }
-      png_to_webp = true
     }
 
     if (!defined(deps)) {