Bug 1430173 - Reduce the precision of all explicit clocks to 2ms. r=baku, a=RyanVM

Backport to ESR where we don't have the ResistFingerprinting component.

MozReview-Commit-ID: 9bjycHjR3SF

--HG--
extra : transplant_source : %EA%03%21%0A%E9%3F%8E%CD%7C%D79f%96%85%96%00%5D%7F%95X

dom/base/moz.build

@@ -143,6 +143,7 @@ EXPORTS.mozilla += [
     'CORSMode.h',
     'FeedWriterEnabled.h',
     'TextInputProcessor.h',
+    'TimerClamping.h',
     'UseCounter.h',
 ]
 
@@ -363,6 +364,7 @@ UNIFIED_SOURCES += [
     'TextInputProcessor.cpp',
     'ThirdPartyUtil.cpp',
     'Timeout.cpp',
+    'TimerClamping.cpp',
     'TreeWalker.cpp',
     'WebKitCSSMatrix.cpp',
     'WebSocket.cpp',