Bug 1083398 - Sprinkle some const keywords around. r=botond

gfx/layers/apz/src/AsyncPanZoomController.cpp

@@ -1776,7 +1776,7 @@ ScreenPoint AsyncPanZoomController::PanStart() const {
   return ScreenPoint(mX.PanStart(), mY.PanStart());
 }
 
-const ScreenPoint AsyncPanZoomController::GetVelocityVector() {
+const ScreenPoint AsyncPanZoomController::GetVelocityVector() const {
   return ScreenPoint(mX.GetVelocity(), mY.GetVelocity());
 }
 

gfx/layers/apz/src/AsyncPanZoomController.h

@@ -491,7 +491,7 @@ protected:
   /**
    * Gets a vector of the velocities of each axis.
    */
-  const ScreenPoint GetVelocityVector();
+  const ScreenPoint GetVelocityVector() const;
 
   /**
    * Gets the first touch point from a MultiTouchInput.  This gets only

gfx/layers/apz/src/Axis.cpp

@@ -320,7 +320,7 @@ CSSCoord Axis::ScaleWillOverscrollAmount(float aScale, CSSCoord aFocus) const {
   return 0;
 }
 
-float Axis::GetVelocity() {
+float Axis::GetVelocity() const {
   return mAxisLocked ? 0 : mVelocity;
 }
 

gfx/layers/apz/src/Axis.h

@@ -151,7 +151,7 @@ public:
   /**
    * Gets the raw velocity of this axis at this moment.
    */
-  float GetVelocity();
+  float GetVelocity() const;
 
   /**
    * Sets the raw velocity of this axis at this moment.