Sometimes selection handler is not moving any direction.

Sometimes selection handler is not moving any direction.

[Version]    N/A
[Project]    Redwood
[Title]      Sometimes selection handler is not moving any direction.
[BinType]    N/A
[Customer]   HQ
[Issue#]     WEB-3432
[Problem]    setBasePositionForMove is setting wrong in handleMouseDown in TextSelection.cpp file
[Cause]      setVisibleContent() from initializeVisibleContentRect() in PageClientImpl.cpp is setting m_visibleContectRect to 0,0
[Solution]   for Image height should not be set half as is happening for the text.
[Team]       WebCoreSupport
[Developer]  deepak.m1@samsung.com
[Request]    N/A
[Horizontal expansion] N/A
[SCMRequest] NA

Change-Id: I602e51d36d69518e5bc75b05fe1bdea01ceb7fba