Removing useless Win7 checks + standardize its use

device/gamepad/gamepad_platform_data_fetcher_win.cc

 // Copyright (c) 2012 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 "device/gamepad/gamepad_platform_data_fetcher_win.h"
 
 #include <stddef.h>
 #include <string.h>
 
 #include "base/bind.h"
@@ skipping 50 matching lines @@
     default:
       return L"<UNKNOWN>";
   }
 }
 
 const UChar* XInputDllFileName() {
   // Xinput.h defines filename (XINPUT_DLL) on different Windows versions, but
   // Xinput.h specifies it in build time. Approach here uses the same values
   // and it is resolving dll filename based on Windows version it is running on.
   if (base::win::GetVersion() >= base::win::VERSION_WIN8) {
-    // For Windows 8 and 10, XINPUT_DLL is xinput1_4.dll.
+    // For Windows 8+, XINPUT_DLL is xinput1_4.dll.
     return FILE_PATH_LITERAL("xinput1_4.dll");
-  } else if (base::win::GetVersion() >= base::win::VERSION_WIN7) {
-    return FILE_PATH_LITERAL("xinput9_1_0.dll");
-  } else {
-    NOTREACHED();
-    return nullptr;
   }
+  return FILE_PATH_LITERAL("xinput9_1_0.dll");
 }
 
 }  // namespace
 
 GamepadPlatformDataFetcherWin::GamepadPlatformDataFetcherWin()
     : xinput_available_(false) {}
 
 GamepadPlatformDataFetcherWin::~GamepadPlatformDataFetcherWin() {
 }
 
@@ skipping 136 matching lines @@
   if (!xinput_get_state_)
     return false;
   if (xinput_enable) {
     // XInputEnable is unavailable before Win8 and deprecated in Win10.
     xinput_enable(true);
   }
   return true;
 }
 
 }  // namespace device