In the emulator, the activity displayed on the call screen of the incoming call is implemented in a class called "com.android.phone.InCallScreen".
Is this true on all Android phones or just unmodified Android software released by Google?
It usually depends on the manufacturer's name such as
com.<manufecturer>.phone.InCallScreen
If you want to check with different devices, Tab Hierarchy Viewer or Devices Eclipse will display the process name on incoming call
Hierarchy Viewer
Devices
process
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