Exit boot animation cleanly.

The desc.txt file can now mark parts as 'must finish cleanly' by using
'c' as the part line prefix rather than 'p'.  If so indicated, if the
bootanimation is asked to quit it will do so only after waiting to
finish that part.

I considered either making init.c service killing smarter or promoting
bootanim to be a bindable service with a requestExit method.  However,
these changes are probably too big/risky given our ship date.  So
I used a property as a mailbox between SurfaceFlinger and bootanim.

Bug: 6679877
Change-Id: Id7dca22caa50b450fff25ca94f7242d971034f41

services/surfaceflinger/SurfaceFlinger.cpp

@@ -148,7 +148,7 @@ void SurfaceFlinger::binderDied(const wp<IBinder>& who)
     setTransactionState(state, eOrientationDefault, 0);
 
     // restart the boot-animation
-    property_set("ctl.start", "bootanim");
+    startBootAnim();
 }
 
 sp<IMemoryHeap> SurfaceFlinger::getCblk() const
@@ -201,7 +201,9 @@ void SurfaceFlinger::bootFinished()
     }
 
     // stop boot animation
-    property_set("ctl.stop", "bootanim");
+    // formerly we would just kill the process, but we now ask it to exit so it
+    // can choose where to stop the animation.
+    property_set("service.bootanim.exit", "1");
 }
 
 static inline uint16_t pack565(int r, int g, int b) {
@@ -306,11 +308,17 @@ status_t SurfaceFlinger::readyToRun()
     mReadyToRunBarrier.open();
 
     // start boot animation
-    property_set("ctl.start", "bootanim");
+    startBootAnim();
 
     return NO_ERROR;
 }
 
+void SurfaceFlinger::startBootAnim() {
+    // start boot animation
+    property_set("service.bootanim.exit", "0");
+    property_set("ctl.start", "bootanim");
+}
+
 // ----------------------------------------------------------------------------
 
 bool SurfaceFlinger::authenticateSurfaceTexture(

services/surfaceflinger/SurfaceFlinger.h

@@ -351,6 +351,8 @@ private:
             void        debugFlashRegions();
             void        drawWormhole() const;
 
+            void        startBootAnim();
+
             void listLayersLocked(const Vector<String16>& args, size_t& index,
                     String8& result, char* buffer, size_t SIZE) const;
             void dumpStatsLocked(const Vector<String16>& args, size_t& index,