Remove legacy StartsWithASCII function.

content/child/blink_platform_impl.cc

Index: content/child/blink_platform_impl.cc
diff --git a/content/child/blink_platform_impl.cc b/content/child/blink_platform_impl.cc
index 41f46d498aef84c6e91b511b56d3941261746e2c..eb0c6241a6122cf5852764ecb89ee4d08a31ceaa 100644
--- a/content/child/blink_platform_impl.cc
+++ b/content/child/blink_platform_impl.cc
@@ -1074,8 +1074,8 @@ WebData BlinkPlatformImpl::loadResource(const char* name) {
     return WebData();
 
   // Check the name prefix to see if it's an audio resource.
-  if (base::StartsWithASCII(name, "IRC_Composite", true) ||
-      base::StartsWithASCII(name, "Composite", true))
+  if (base::StartsWith(name, "IRC_Composite", base::CompareCase::SENSITIVE) ||
+      base::StartsWith(name, "Composite", base::CompareCase::SENSITIVE))
     return loadAudioSpatializationResource(name);
 
   // TODO(flackr): We should use a better than linear search here, a trie would