Add screen power save block level.

content/browser/power_save_blocker_mac.cc

Index: content/browser/power_save_blocker_mac.cc
diff --git a/content/browser/power_save_blocker_mac.cc b/content/browser/power_save_blocker_mac.cc
index 9acd130f53931a6ff46594f9489e80cddf4b29ca..bdcf6f4d65a303af1712bafab04ec1fa4a2c8c63 100644
--- a/content/browser/power_save_blocker_mac.cc
+++ b/content/browser/power_save_blocker_mac.cc
@@ -6,6 +6,7 @@
 
 #include <IOKit/pwr_mgt/IOPMLib.h>
 
+#include "base/bind.h"
 #include "base/threading/platform_thread.h"
 #include "base/threading/thread.h"
 #include "content/browser/browser_thread.h"
@@ -19,35 +20,44 @@ namespace {
 base::Thread* g_power_thread;
 IOPMAssertionID g_power_assertion;
 
-void CreateSleepAssertion() {
+void CreateSleepAssertion(PowerSaveBlocker::PowerSaveBlockerType type) {
   DCHECK_EQ(base::PlatformThread::CurrentId(), g_power_thread->thread_id());
   IOReturn result;
-  DCHECK_EQ(g_power_assertion, kIOPMNullAssertionID);
 
-  // Block just idle sleep; allow display sleep.
-  // See QA1340 <http://developer.apple.com/library/mac/#qa/qa2004/qa1340.html>
-  // for more details.
-  result = IOPMAssertionCreate(kIOPMAssertionTypeNoIdleSleep,
-                               kIOPMAssertionLevelOn,
-                               &g_power_assertion);
-  LOG_IF(ERROR, result != kIOReturnSuccess)
-      << "IOPMAssertionCreate: " << result;
-}
+  if (g_power_assertion != kIOPMNullAssertionID) {
+    result = IOPMAssertionRelease(g_power_assertion);
+    g_power_assertion = kIOPMNullAssertionID;
+    LOG_IF(ERROR, result != kIOReturnSuccess)
+        << "IOPMAssertionRelease: " << result;
+  }
 
-void ReleaseSleepAssertion() {
-  DCHECK_EQ(base::PlatformThread::CurrentId(), g_power_thread->thread_id());
-  IOReturn result;
-  DCHECK_NE(g_power_assertion, kIOPMNullAssertionID);
-  result = IOPMAssertionRelease(g_power_assertion);
-  g_power_assertion = kIOPMNullAssertionID;
-  LOG_IF(ERROR, result != kIOReturnSuccess)
-      << "IOPMAssertionRelease: " << result;
+  CFStringRef level = NULL;
+  // See QA1340 <http://developer.apple.com/library/mac/#qa/qa1340/> for more
+  // details.
+  switch (type) {
+    case PowerSaveBlocker::kPowerSaveBlockPreventSystemSleep:
+      level = kIOPMAssertionTypeNoIdleSleep;
+      break;
+    case PowerSaveBlocker::kPowerSaveBlockPreventDisplaySleep:
+      level = kIOPMAssertionTypeNoDisplaySleep;
+      break;
+    default:

[Mark Mentovai, 2011/10/13 19:09:13]

You can make this be |case kPowerSaveBlockPreventNone:| instead of |default:|.
Then, when someone adds a new value to the enum, the compiler will warn at this
switch about an unhandled value, which will prompt that same someone to come
here and make the code handle the new enum value.

+      break;
+  }
+  if (level) {
+    result = IOPMAssertionCreate(level,
+                                 kIOPMAssertionLevelOn,
+                                 &g_power_assertion);
+    LOG_IF(ERROR, result != kIOReturnSuccess)
+        << "IOPMAssertionCreate: " << result;
+  }
 }
 
 }  // namespace
 
 // Called only from UI thread.
-void PowerSaveBlocker::ApplyBlock(bool blocking) {
+// static
+void PowerSaveBlocker::ApplyBlock(PowerSaveBlockerType type) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
 
   if (!g_power_thread) {
@@ -56,9 +66,6 @@ void PowerSaveBlocker::ApplyBlock(bool blocking) {
     g_power_thread->Start();
   }
 
-  MessageLoop* loop = g_power_thread->message_loop();
-  if (blocking)
-    loop->PostTask(FROM_HERE, NewRunnableFunction(CreateSleepAssertion));
-  else
-    loop->PostTask(FROM_HERE, NewRunnableFunction(ReleaseSleepAssertion));
+  g_power_thread->message_loop()->
+      PostTask(FROM_HERE, base::Bind(CreateSleepAssertion, type));
 }