Add quiet safe browsing interstitial for WebView

BUG=716095

Review-Url: https://codereview.chromium.org/2854263003
Cr-Commit-Position: refs/heads/master@{#473150}
diff --git a/components/security_interstitials_strings.grdp b/components/security_interstitials_strings.grdp
index 51b64d82..6693485eb 100644
--- a/components/security_interstitials_strings.grdp
+++ b/components/security_interstitials_strings.grdp
@@ -186,4 +186,18 @@
     You can <ph name="BEGIN_ERROR_LINK">&lt;a href="#" id="report-error-link"&gt;</ph>report a detection problem<ph name="END_ERROR_LINK">&lt;/a&gt;</ph> or, if you understand the risks to your security, <ph name="BEGIN_LINK">&lt;a href="#" id="proceed-link"&gt;</ph>visit this unsafe site<ph name="END_LINK">&lt;/a&gt;</ph>.
   </message>
 
+  <!-- WebView Safe Browsing quiet interstitals medium sized -->
+  <message name="IDS_MALWARE_WEBVIEW_HEADING" desc="The heading of the malware interstitial on medium sized Webview.">
+    Dangerous content blocked
+  </message>
+  <message name="IDS_MALWARE_WEBVIEW_EXPLANATION_PARAGRAPH" desc="The explanation of why Safe Browsing has blocked the page. Allows the user to proceed using a link.">
+    This content might try to install dangerous software on your device that steals or deletes your information. <ph name="BEGIN_LINK">&lt;a href="#" id="proceed-link"&gt;</ph>Show anyway<ph name="END_LINK">&lt;/a&gt;</ph>.
+  </message>
+  <message name="IDS_PHISHING_WEBVIEW_HEADING" desc="The heading of the phishing interstitial on medium sized Webview.">
+    Deceptive content blocked
+  </message>
+  <message name="IDS_PHISHING_WEBVIEW_EXPLANATION_PARAGRAPH" desc="The explanation of why Safe Browsing has blocked the page. Allows the user to proceed using a link.">
+    This content might try to trick you into installing software or revealing personal information. <ph name="BEGIN_LINK">&lt;a href="#" id="proceed-link"&gt;</ph>Show anyway<ph name="END_LINK">&lt;/a&gt;</ph>.
+  </message>
+
 </grit-part>