hwc: Fix locking.

Remove the unnecessary blank lock, mdp comp lock, secure lock.
Rename the ext lock to a more appropriate draw lock.

The mdp comp lock is at an incorrect place and causes unwanted
objects to show up in dumpsys, since configDone hasnt cleaned
them up yet.

dump(), blank(), draw() should all acquire a common lock.
draw() includes prepare() and set().

Change-Id: I595547dd5a393a8af6cd8c9297d50793b715e658
diff --git a/libhwcomposer/hwc_uevents.cpp b/libhwcomposer/hwc_uevents.cpp
index 1d127f0..916b346 100644
--- a/libhwcomposer/hwc_uevents.cpp
+++ b/libhwcomposer/hwc_uevents.cpp
@@ -125,7 +125,7 @@
                 break;
             }
 
-            Locker::Autolock _l(ctx->mExtLock);
+            Locker::Autolock _l(ctx->mDrawLock);
             clear(ctx, dpy);
             ctx->dpyAttr[dpy].connected = false;
             ctx->dpyAttr[dpy].isActive = false;
@@ -164,7 +164,7 @@
                 //fail, since Layer Mixer#0 is still connected to WriteBack.
                 //This block will force composition to close fb2 in above
                 //example.
-                Locker::Autolock _l(ctx->mExtLock);
+                Locker::Autolock _l(ctx->mDrawLock);
                 ctx->dpyAttr[dpy].isConfiguring = true;
                 ctx->proc->invalidate(ctx->proc);
             }
@@ -177,7 +177,7 @@
                     ALOGD_IF(UEVENT_DEBUG,"Received HDMI connection request"
                              "when WFD is active");
                     {
-                        Locker::Autolock _l(ctx->mExtLock);
+                        Locker::Autolock _l(ctx->mDrawLock);
                         clear(ctx, HWC_DISPLAY_VIRTUAL);
                         ctx->dpyAttr[HWC_DISPLAY_VIRTUAL].connected = false;
                         ctx->dpyAttr[HWC_DISPLAY_VIRTUAL].isActive = false;
@@ -193,7 +193,7 @@
                         ctx->proc->hotplug(ctx->proc, HWC_DISPLAY_EXTERNAL,
                                            EXTERNAL_OFFLINE);
                         {
-                            Locker::Autolock _l(ctx->mExtLock);
+                            Locker::Autolock _l(ctx->mDrawLock);
                             ctx->mVirtualonExtActive = false;
                         }
                     }
@@ -205,7 +205,7 @@
                 ctx->mExtDisplay->configure();
             } else {
                 {
-                    Locker::Autolock _l(ctx->mExtLock);
+                    Locker::Autolock _l(ctx->mDrawLock);
                     /* TRUE only when we are on proprietary WFD session */
                     ctx->mVirtualonExtActive = true;
                     char property[PROPERTY_VALUE_MAX];
@@ -220,7 +220,7 @@
                 ctx->mVirtualDisplay->configure();
             }
 
-            Locker::Autolock _l(ctx->mExtLock);
+            Locker::Autolock _l(ctx->mDrawLock);
             setup(ctx, dpy);
             ctx->dpyAttr[dpy].isPause = false;
             ctx->dpyAttr[dpy].connected = true;
@@ -255,7 +255,7 @@
             //Since external didnt have any pipes, force primary to give up
             //its pipes; we don't allow inter-mixer pipe transfers.
             {
-                Locker::Autolock _l(ctx->mExtLock);
+                Locker::Autolock _l(ctx->mDrawLock);
                 ctx->dpyAttr[dpy].isConfiguring = true;
                 ctx->dpyAttr[dpy].isActive = true;
                 ctx->proc->invalidate(ctx->proc);
@@ -264,7 +264,7 @@
                    * 2 / 1000);
             {
                 //At this point external has all the pipes it  would need.
-                Locker::Autolock _l(ctx->mExtLock);
+                Locker::Autolock _l(ctx->mDrawLock);
                 ctx->dpyAttr[dpy].isPause = false;
                 ctx->proc->invalidate(ctx->proc);
             }