Reland of place string::find(prefix) == 0 pattern with base::StartsWith().

media/blink/resource_multibuffer_data_provider.cc

Index: media/blink/resource_multibuffer_data_provider.cc
diff --git a/media/blink/resource_multibuffer_data_provider.cc b/media/blink/resource_multibuffer_data_provider.cc
index e107270af0f937a27b20123ef3d8375b122e1a46..d8f3458330c1ab8b010ac9d947786cd26962903f 100644
--- a/media/blink/resource_multibuffer_data_provider.cc
+++ b/media/blink/resource_multibuffer_data_provider.cc
@@ -14,6 +14,7 @@
 #include "base/metrics/histogram.h"
 #include "base/single_thread_task_runner.h"
 #include "base/strings/string_number_conversions.h"
+#include "base/strings/string_util.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "media/blink/active_loader.h"
 #include "media/blink/cache_util.h"
@@ -461,11 +462,13 @@
     int64_t* first_byte_position,
     int64_t* last_byte_position,
     int64_t* instance_size) {
-  const std::string kUpThroughBytesUnit = "bytes ";
-  if (content_range_str.find(kUpThroughBytesUnit) != 0)
-    return false;
+  const char kUpThroughBytesUnit[] = "bytes ";
+  if (!base::StartsWith(content_range_str, kUpThroughBytesUnit,
+                        base::CompareCase::SENSITIVE)) {
+    return false;
+  }
   std::string range_spec =
-      content_range_str.substr(kUpThroughBytesUnit.length());
+      content_range_str.substr(sizeof(kUpThroughBytesUnit) - 1);
   size_t dash_offset = range_spec.find("-");
   size_t slash_offset = range_spec.find("/");