Remove include of <time.h> from fpdfsdk/cpdfsdk_datetime.h

Prevent stray calls to get time from the system without explicilty
including <time.h> in some .cpp file.  This helps to be able to control
all the places where PDFium obtains time more carefully.

Change-Id: I9d52a00b9d4413e18c98f0476fabe7c5f2cd6574
Reviewed-on: https://pdfium-review.googlesource.com/39710
Commit-Queue: Tom Sepez <tsepez@chromium.org>
Commit-Queue: Ryan Harrison <rharrison@chromium.org>
Reviewed-by: Ryan Harrison <rharrison@chromium.org>

fpdfsdk/cpdfsdk_datetime.h

diff --git a/fpdfsdk/cpdfsdk_datetime.h b/fpdfsdk/cpdfsdk_datetime.h
index cbd3c36..08d8c2b 100644
--- a/fpdfsdk/cpdfsdk_datetime.h
+++ b/fpdfsdk/cpdfsdk_datetime.h
@@ -7,12 +7,6 @@
 #ifndef FPDFSDK_CPDFSDK_DATETIME_H_
 #define FPDFSDK_CPDFSDK_DATETIME_H_
 
-#if _FX_OS_ == _FX_OS_ANDROID_
-#include <time.h>
-#else
-#include <ctime>
-#endif
-
 #include "fpdfsdk/cfx_systemhandler.h"
 
 class CPDFSDK_DateTime {