Convert Devtools protocol Input timestamp to monotonic clock

content/browser/devtools/protocol/input_handler.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/browser/devtools/protocol/input_handler.h"
 
 #include <stddef.h>
 
 #include "base/message_loop/message_loop.h"
 #include "base/strings/stringprintf.h"
@@ skipping 51 matching lines @@
     event->modifiers |= blink::WebInputEvent::AltKey;
   if (*modifiers & 2)
     event->modifiers |= blink::WebInputEvent::ControlKey;
   if (*modifiers & 4)
     event->modifiers |= blink::WebInputEvent::MetaKey;
   if (*modifiers & 8)
     event->modifiers |= blink::WebInputEvent::ShiftKey;
 }
 
 void SetEventTimestamp(blink::WebInputEvent* event, const double* timestamp) {
-  event->timeStampSeconds =
-      timestamp ? *timestamp : base::Time::Now().ToDoubleT();
+  // Convert timestamp, in seconds since unix epoch, to an event timestamp
+  // which is time ticks since platform start time.
+  base::TimeTicks ticks = timestamp
+                              ? base::TimeDelta::FromSecondsD(*timestamp) +
+                                    base::TimeTicks::UnixEpoch()
+                              : base::TimeTicks::Now();
+  event->timeStampSeconds = (ticks - base::TimeTicks()).InSecondsF();
 }
 
 bool SetKeyboardEventText(blink::WebUChar* to, const std::string* from) {
   if (!from)
     return true;
 
   base::string16 text16 = base::UTF8ToUTF16(*from);
   if (text16.size() > blink::WebKeyboardEvent::textLengthCap)
     return false;
 
@@ skipping 428 matching lines @@
   } else {
     client_->SendError(command_id,
                        Response::InternalError(base::StringPrintf(
                            "Synthetic tap failed, result was %d", result)));
   }
 }
 
 }  // namespace input
 }  // namespace devtools
 }  // namespace content