Android: Add temporary alias for webui resources

The android_clang_arm subdirectory is used during the build for 64-bit
builds. These generated resources need a similar alias to be accessible
in chrome pages like chrome://offline-internals. This is a temporary fix
to add the missing alias.

A long-term fix should resolve @out_dir@ to include android_clang_arm or
something similar.

Bug: 1020284
Change-Id: Ibf5f422dc38d77ea984ad576f9e36ddf5fe868d1
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1928556
Auto-Submit: Peter Wen <wnwen@chromium.org>
Reviewed-by: Demetrios Papadopoulos <dpapad@chromium.org>
Commit-Queue: Demetrios Papadopoulos <dpapad@chromium.org>
Commit-Queue: Peter Wen <wnwen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#717709}

content/browser/webui/shared_resources_data_source.cc

@@ -61,17 +61,20 @@ const std::map<std::string, std::string> CreatePathPrefixAliasesMap() {
   // TODO(rkc): Once we have a separate source for apps, remove '*/apps/'
   // aliases.
   std::map<std::string, std::string> aliases = {
-      {"../../../third_party/polymer/v1_0/components-chromium/",
-       "polymer/v1_0/"},
-      {"../../../third_party/polymer/v3_0/components-chromium/",
-       "polymer/v3_0/"},
-      {"../../../third_party/web-animations-js/sources/",
-       "polymer/v1_0/web-animations-js/"},
-      {"../../views/resources/default_100_percent/common/", "images/apps/"},
-      {"../../views/resources/default_200_percent/common/", "images/2x/apps/"},
-      {"../../webui/resources/cr_components/", "cr_components/"},
-      {"../../webui/resources/cr_elements/", "cr_elements/"},
-      {"@out_folder@/gen/ui/webui/resources/", ""},
+    {"../../../third_party/polymer/v1_0/components-chromium/", "polymer/v1_0/"},
+    {"../../../third_party/polymer/v3_0/components-chromium/", "polymer/v3_0/"},
+    {"../../../third_party/web-animations-js/sources/",
+     "polymer/v1_0/web-animations-js/"},
+    {"../../views/resources/default_100_percent/common/", "images/apps/"},
+    {"../../views/resources/default_200_percent/common/", "images/2x/apps/"},
+    {"../../webui/resources/cr_components/", "cr_components/"},
+    {"../../webui/resources/cr_elements/", "cr_elements/"},
+    {"@out_folder@/gen/ui/webui/resources/", ""},
+#if defined(OS_ANDROID)
+    // This is a temporary fix for `target_cpu = "arm64"`. See the bug for
+    // more context: crbug.com/1020284.
+    {"@out_folder@/android_clang_arm/gen/ui/webui/resources/", ""},
+#endif  // defined(OS_ANDROID)
   };
 
 #if defined(OS_CHROMEOS)