Catch EvalError thrown by element.js in translate.

CSP can prevent eval and will cause this error:
"refused to evaluate a string as javascript because 'unsafe-eval'"

This fails silently on iOS so we need to catch it.

Bug: 686364
Change-Id: I5de275576670846dffc29f9f2c3916259196e70f
Reviewed-on: https://chromium-review.googlesource.com/1183944Reviewed-by: David Roger <droger@chromium.org>
Commit-Queue: John Wu <jzw@chromium.org>
Cr-Commit-Position: refs/heads/master@{#586055}

components/translate/core/browser/resources/translate.js

@@ -301,6 +301,16 @@ cr.googleTranslate = (function() {
       lib.restore();
     },
 
+    /**
+     * Called when an error is caught while executing script fetched in
+     * translate_script.cc.
+     */
+    onTranslateElementError: function(error) {
+      errorCode = ERROR['UNEXPECTED_SCRIPT_ERROR'];
+      // Delayed so |readyCallback| has time to be defined.
+      setTimeout(invokeReadyCallback, 100);
+    },
+
     /**
      * Entry point called by the Translate Element once it has been injected in
      * the page.

components/translate/core/browser/translate_script.cc

@@ -161,7 +161,14 @@ void TranslateScript::OnScriptFetchComplete(bool success,
         ui::ResourceBundle::GetSharedInstance().GetRawDataResource(
             IDR_TRANSLATE_JS);
     str.AppendToString(&data_);
-    data_ += data;
+    // Wrap |data| in try/catch block to handle unexpected script errors.
+    const char* format =
+        "try {"
+        "  %s;"
+        "} catch (error) {"
+        "  cr.googleTranslate.onTranslateElementError(error);"
+        "};";
+    base::StringAppendF(&data_, format, data.c_str());
 
     // We'll expire the cached script after some time, to make sure long
     // running browsers still get fixes that might get pushed with newer