Remove getSafetyNetId interface in SafeBrowsingApiHandler.

Now that the implementation in internal repository is removed, it is
safe to remove the interface.

Bug: 1070836
Change-Id: I196df7afd48dd051b2f8e053166248eedd24305b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2168648Reviewed-by: Yaron Friedman <yfriedman@chromium.org>
Commit-Queue: Xinghui Lu <xinghuilu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#763456}

android_webview/javatests/src/org/chromium/android_webview/test/SafeBrowsingTest.java

@@ -147,11 +147,6 @@ public class SafeBrowsingTest {
         // Mock time it takes for a lookup request to complete.
         private static final long CHECK_DELTA_US = 10;
 
-        @Override
-        public String getSafetyNetId() {
-            return "";
-        }
-
         @Override
         public boolean init(Observer result) {
             mObserver = result;

chrome/android/javatests/src/org/chromium/chrome/browser/MockSafeBrowsingApiHandler.java

@@ -34,11 +34,6 @@ public class MockSafeBrowsingApiHandler implements SafeBrowsingApiHandler {
 
     private HashMap<String, String> mResponseMap;
 
-    @Override
-    public String getSafetyNetId() {
-        return "";
-    }
-
     @Override
     public boolean init(Observer observer) {
         mObserver = observer;

components/safe_browsing/android/java/src/org/chromium/components/safe_browsing/SafeBrowsingApiHandler.java

@@ -46,18 +46,6 @@ public interface SafeBrowsingApiHandler {
      */
     public boolean init(Observer result);
 
-    /**
-     * Returns the Safety Net ID of the device. Checks to make sure that the feature to report
-     * telemetry for APK downloads is enabled. This should not be called for AW.
-     *
-     * @return the Safety Net ID of the device.
-     */
-    // TODO(crbug.com/1070836): Remove this interface once internal repository implementation is
-    // removed.
-    public default String getSafetyNetId() {
-        return "";
-    }
-
     /**
      * Start a URI-lookup to determine if it matches one of the specified threats.
      * This is called on every URL resource Chrome loads, on the same sequence as |init|.