overlay: Add support for pipe dumps.

Add support for pipe state dump useful in dumpsys.
Reduce debug log spam when mdp state changes.

Change-Id: Ie27ad00698085e2ffd6166ad2f7503fe16a571f8
diff --git a/liboverlay/overlayCtrlData.h b/liboverlay/overlayCtrlData.h
index 0c49bdd..c9a4949 100644
--- a/liboverlay/overlayCtrlData.h
+++ b/liboverlay/overlayCtrlData.h
@@ -81,9 +81,6 @@
     /* retrieve cached crop data */
     utils::Dim getCrop() const;
 
-    /* dump the state of the object */
-    void dump() const;
-
     /* Perform transformation calculations */
     void doTransform();
 
@@ -96,6 +93,12 @@
     /* Update the src format */
     void updateSrcformat(const uint32_t& inputsrcFormat);
 
+    /* dump the state of the object */
+    void dump() const;
+
+    /* Return the dump in the specified buffer */
+    void getDump(char *buf, size_t len);
+
 private:
     /* Retrieve screen info from underlying mdp */
     bool getScreenInfo(utils::ScreenInfo& info);
@@ -134,6 +137,9 @@
     /* sump the state of the obj */
     void dump() const;
 
+    /* Return the dump in the specified buffer */
+    void getDump(char *buf, size_t len);
+
 private:
     // mdp data struct
     MdpData mMdp;
@@ -213,6 +219,10 @@
     return mMdp.getDownscalefactor();
 }
 
+inline void Ctrl::getDump(char *buf, size_t len) {
+    mMdp.getDump(buf, len);
+}
+
 inline Data::Data() {
     mMdp.reset();
 }
@@ -249,6 +259,9 @@
     ALOGE("== Dump Data MDP end ==");
 }
 
+inline void Data::getDump(char *buf, size_t len) {
+    mMdp.getDump(buf, len);
+}
 
 } // overlay