Remove default NOP implementation of MonotonicallyIncreasingTime.

BUG=417668
LOG=N
R=jochen@chromium.org

Review URL: https://codereview.chromium.org/641653002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@24489 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

include/v8-platform.h

@@ -56,7 +56,6 @@ class Platform {
    */
   virtual void CallOnForegroundThread(Isolate* isolate, Task* task) = 0;
 
-
   /**
    * Monotonically increasing time in seconds from an arbitrary fixed point in
    * the past. This function is expected to return at least
@@ -64,11 +63,7 @@ class Platform {
    * it is recommended that the fixed point be no further in the past than
    * the epoch.
    **/
-  virtual double MonotonicallyIncreasingTime() {
-    // TODO(rmcilroy): Remove this default implementation when Chromium
-    // change has landed.
-    return 0;
-  }
+  virtual double MonotonicallyIncreasingTime() = 0;
 };
 
 }  // namespace v8